Part 3 of the Knowledge Organisation Systems Chain in our Skills for Modern Technical Communicators series
Knowledge Organisation System (KOS) is an umbrella term for the tools and frameworks used to structure and manage information so it can be found, related, and reused. The larger KOS journey goes through the following transformations: raw data → structured data → vocabularies/taxonomies → ontologies → knowledge graphs → intelligent services
This is the third post in our KOS series. In this one, I’ll define ontologies and semantic models in practical terms; explain why standards matter (SKOS for labels, OWL for logic, and where SHACL fits); walk a step‑by‑step pipeline to transform a taxonomy into an ontology; validate with SHACL; and close with use cases, a case study, and a pilot you can run this quarter.
But before we get practical, here’s the short poem I wrote this week to set the tone:
From names and lists we start to climb,
– CJ Walker
From parent–child to truth in time
Add rules and links the world can read,
So meaning flows where users need.
Taxonomies are necessary but not sufficient. They give you consistent labels and tidy hierarchies; great for navigation and tagging.
Ontologies make those labels work harder: they encode what things are, how they relate, and what must be true. That shift enables consistency checks, smarter reuse, cross‑system integration, and answers that go beyond keyword match.
Why should technical communicators care about this? Because ontologies are where content governance meets intelligent systems. They reduce ambiguity, catch contradictions, and power automation. It also opens new career paths – from ContentOps to knowledge engineering – for technical communicators who can model information as predictably as they craft sentences.
Controlled Vocabularies and Taxonomies: The Launchpad
Here’s how the transformation works, and how to put it to work for you.
Let’s go back to the previous step to ground our starting point for what ontologies build on:
- Controlled vocabulary: An agreed list of preferred terms, with definitions, aliases, and usage notes. Think: “Sign‑in” (preferred), “login” (alias), “log‑in” (alias), each with a definition and context of use.
- Taxonomy: A structured arrangement of those terms, usually hierarchical (broader/narrower) with simple relationships. Think: Product → Feature → Subfeature; Error → Category → Subcategory.
Vocabularies and taxonomies deliver:
- Consistent naming and tagging
- Better navigation and findability
- Reduced translation inconsistencies
- Shared language across teams
But they have limits. Hierarchies don’t express rich relationships (“requires,” “affects,” “deprecated by”), they don’t enforce constraints (“a feature must belong to one product”), and they can’t support automated checks (“if version ≥ 5, show prerequisite X”).
That’s the gap that ontologies fill.
An Ontology is Practical, not Mystical
If your taxonomy is a map of labels, your ontology is a map of meaning. So what is an “ontology”? For our purposes, it is a formal, machine‑readable semantic model of a domain.
“Semantic model” is the broader term: it encodes meaning—entities, relationships, and rules, so data is unambiguous across systems. An ontology is a specific kind of semantic model that adds explicit logic and constraints for reasoning.
An ontology defines:
- Classes (types of things): Product, Feature, Error, Procedure, Role
- Properties (relationships and attributes): hasFeature, affectsVersion, requiresPrerequisite, severity
- Constraints and rules: a Feature must belong to exactly one Product; a ProcedureStep must have an expectedOutcome; Error severity ∈ {Low, Medium, High}
- Instances (actual things): “WidgetPro 6.2,” “Error E55,” “Install Driver Step 3”
It makes relationships explicit and enforceable, which unlocks:
- Reasoning (infer new facts, detect contradictions)
- Integration (align systems through shared semantics)
- Validation (catch gaps and mismatches automatically)
- Reuse (assemble content by logic, not manual linking)
For technical communicators, think of it as content modeling turned into logic your tools can understand and enforce.
SKOS Standard vs. OWL Standard: From Labels to Logic
In this context, standards are open, widely adopted specifications for how to represent vocabularies and ontologies. They provide shared data shapes, identifiers, and semantics so different tools and teams can describe the same things the same way.
You need standards because they enable interoperability across systems, allow governance and validation to be automated, make models portable (no bespoke one‑offs), and future‑proof your work with vendor‑neutral formats and multilingual support.
Two standards matter here:
- SKOS
(Simple Knowledge Organization System) models vocabularies and taxonomies—concepts, labels, preferred/alternative terms, broader/narrower.
It’s for curating concepts and labels (your editorial surface) - OWL
(Web Ontology Language) models semantic models (ontologies)—classes, properties, constraints, axioms, and reasoning.
It’s for encoding what those concepts are allowed to do (your logic and constraints)
In practice, SKOS preserves the vocabulary people manage, and OWL adds the rules engines can reason over: labels on one side, logic on the other, working in tandem.
Transforming taxonomy to ontology often looks like:
- Keep SKOS for human‑managed labels and multilingual terms
- Introduce OWL for classes, properties, and constraints
- Link them: SKOS concepts align to OWL classes or individuals where appropriate
This hybrid approach preserves editorial control (terms, definitions) while adding machine‑level meaning (rules, logic).
The Transformation Pipeline: From Vocabulary/Taxonomy to Ontology
Pipelines beat heroics in my experience. A simple, repeatable sequence will outperform ad‑hoc modeling and make reliability boring in the best possible way.
Here’s a practical, tool‑agnostic pipeline:
- Inventory and Align Terms
- Audit your controlled vocabulary and taxonomy (preferred terms, aliases, definitions, broader/narrower links).
- Consolidate duplicates; fix ambiguous or overlapping concepts.
- Decide which taxonomy concepts represent “types of things” (classes) versus “topics/labels” (still SKOS concepts).
Outcome: A clean term base with candidates for classes.
- Identify Domain Entities and Scope
- List core entities: Product, Feature, Version, Platform, Error, Procedure, Role, Environment, Audience.
- Define attributes: Product hasVersion, Feature hasStatus, Error hasSeverity, ProcedureStep hasExpectedOutcome.
- Identify key relationships: Feature belongsTo Product; Error affects Feature; Procedure requires Role; Procedure targets Platform.
Outcome: A minimal domain model that mirrors your content patterns.
- Map Hierarchy to Rich Relationships
- Replace “parent/child” where needed with typed relationships: Feature partOf Product; Error occursIn Environment; ProcedureStep precedes another Step.
- Keep taxonomic hierarchy where it’s truly broader/narrower; otherwise move to properties.
Outcome: Relationships that mean something beyond navigation.
- Define Constraints and Cardinalities
- Specify “must/should/can’t” rules: each Feature belongsTo exactly 1 Product; a ProcedureStep must have ≥1 StepInstruction; Error severity ∈ {Low, Medium, High}.
- Set value ranges and enumerations for critical fields.
Outcome: Logic that enables automated validation and reasoning.
- Align to Standards (SKOS/OWL) and Create URIs
- Represent vocabulary/taxonomy in SKOS (preferred labels, alt labels, definitions).
- Represent ontology in OWL (classes, object/datatype properties, axioms).
- Assign stable URIs/IDs for everything (classes, properties, instances).
Outcome: A durable model that systems and teams can reference consistently.
- Add Validation (SHACL) and Test Data
- Use SHACL (Shapes Constraint Language) to enforce required properties and allowed values on instances.
- Load a small set of real instances (a few products, features, procedures, errors) and run validation.
Outcome: Early detection of gaps and rule conflicts.
- Governance and Change Protocols
- Define ownership for vocabulary, taxonomy, and ontology (they rarely share the same steward).
- Set review cadence; track changes with versioning.
- Add change impact checks (what breaks if we alter a class or property?).
Outcome: An ontology that doesn’t quietly drift out of sync with reality.
Each step reduces ambiguity and increases value. Don’t aim for completeness; aim for a working slice that proves useful and can scale.
Where This Fits in the Knowledge Organisation Systems (KOS) Stack
Now we need to zoom out to look at the bigger picture. Taxonomies aren’t the finish line; ontologies are the platform that lets graphs and services do real work across products and teams.
Raw data and structured data are the first two rungs in a larger KOS ladder that technical communicators increasingly work across. Your friendly reminder of the process:
- Raw data: Unprocessed signals
- Structured data: Predictable shapes and rules
- Controlled vocabularies and taxonomies: Agreed terms and hierarchical relationships
- Ontologies and semantic models: Rich relationships (beyond parent/child) and constraints that carry meaning; “semantic model” is the general layer that describes meaning, and an ontology is the formal, OWL‑expressed semantic model that supports reasoning and validation
- Knowledge graph is the populated network: ontology + instances (actual products, features, errors, versions) expressed as triples with URIs, provenance, and links across sources (what does exist right now and how it’s connected)
- Semantic power: Search, recommendations, personalisation, QA checks, and AI assistants powered by the layers beneath
Ontologies are the pivot point. Without them, knowledge graphs are brittle and services stay shallow. With them, everything above becomes feasible and scalable.
Why Technical Communicators Should Care
You should care because ontologies are career rocket fuel. They cut noise, prove impact, and move you from page production to system design.
Here’s a list of practical benefits of the specific, measurable advantages you can expect when you elevate taxonomies into ontologies and validate instances. Use it to align efforts, set baselines, and track gains over time.
- Precision and consistency: Ontology rules enforce consistent fields, relationships, and terminology. This reduces ambiguity and translation errors, improves readability, and makes quality measurable.
- Automation and reuse: When relationships and constraints are explicit, you can assemble variants by logic, auto‑flag dependencies, and cut maintenance debt.
- Analytics and decision-making: Ontology‑backed queries reveal which relationships and prerequisites drive outcomes (reduced tickets, improved task success). You can prove—and improve—value.
- Faster change propagation: With stable URIs and typed relationships, a single update can cascade to dependent pages, PDFs, tooltips, and training without manual hunts.
- Compliance and risk control: SHACL validation and ontology constraints catch gaps before release. In regulated domains, ontology‑backed validation is a real safety net.
- Career leverage: Skills in SKOS/OWL modelling, SHACL validation, and semantic integration translate into roles in content operations, knowledge engineering, and systems architecture.
Practical Use Cases
Start where you already have pain. These patterns slot into existing workflows and show results in weeks, not quarters.
- Product docs: Model Product–Feature–Version relationships with constraints (for example, deprecatedInVersion). Drive “What’s new,” release notes, and API diffs from the same ontology‑backed instances.
- Troubleshooting: Encode Error–Symptom–RootCause–Remedy patterns with occurs In Environment and required prerequisites. Power guided flows and chatbot answers with reasoning and validation.
- UI text and microcopy: Treat UI strings as instances bound to classes (UIComponent, UIState, Locale). Manage tone, terminology, and accessibility at scale.
- Knowledge bases: Use ontology‑aligned templates that enforce required fields and connect to upstream sources (support systems, error telemetry).
- Training and compliance: Tie procedures to roles, permissions, and evidence requirements. Generate task-based training variants with ontology‑driven assembly.
Case Study: From Taxonomy to Actionable Knowledge
Here’s a practical walk-through of turning a controlled vocabulary and taxonomy into a structured troubleshooting system your team can maintain.
Scenario
An SaaS company has a taxonomy of error categories (Authentication, Networking, Storage) and a controlled vocabulary for error names, but steps and prerequisites remain inconsistent across dozens of pages.
Step 1
Stabilise vocabulary and taxonomy. Create canonical error codes/names with aliases in SKOS; fix broader/narrower overlaps and ambiguous parents.
Step 2
Introduce a minimal ontology slice.
Classes: Error, Symptom, RootCause, Remedy, Environment, ProductVersion. Properties: presentsSymptom, causedBy, resolvedBy, occursIn, affectsVersion.
Constraints: every Error must present ≥1 Symptom and have ≥1 Remedy; Environment ∈ approved list.
Step 3
Add SHACL validation. Enforce required properties and allowed values; block publication on shape violations.
Step 4
Connect upstream signals. Link telemetry and ticket IDs to Error instances; auto‑flag ontology‑linked docs when upstream signals change.
Results
At Firehead, we’ve seen teams cut update time per issue by ~40% within just six weeks, eliminate duplicate error names, and reduce support escalations tied to outdated steps by ~25%. The ontology also caught incomplete remedies and inconsistent environments before publication.
Assimilate KOS into Your TechComm Workflow
Here’s a learning plan that bridges the case study into action. It’s a tool‑agnostic, small‑pilot roadmap designed to embed ontology into everyday techcomm work and deliver measurable gains: faster updates, fewer duplicates, and automatic change flags.
You can apply this to move from ad‑hoc fixes to a repeatable system you can scale.
Objective: Operationalise a minimal ontology layered over your existing vocabulary/taxonomy, then scale.
Scope: One workflow with clear pain (for example, troubleshooting for a single product area).
Baseline (now) and Targets (8–12 weeks):
- Time to update an article → −30–40%
- Duplicate/alias error names → −50%
- Validation failures caught pre‑publication → +60–80%
– Support escalations tied to doc issues → −20–25%
Phase 1 — Foundation (Weeks 1–2)
- Inventory controlled vocabulary and taxonomy; fix duplicates and ambiguous concepts
- Establish a minimal controlled vocabulary (preferred terms + aliases)
Outcome: Clean term base with clear candidate classes.
Phase 2 — Ontology Slice (Weeks 3–4)
- Identify core classes and properties; define cardinalities and allowed values
- Create a lightweight OWL model and enable basic validation
Outcome: Minimal ontology ready for validation
Phase 3 — Integration (Weeks 5–6)
- Create SHACL shapes; load a small set of real instances
- Connect telemetry/ticket IDs; auto‑flag impacted docs on change
Outcome: Signals trigger the right doc updates; validation catches gaps
Phase 4 — Operations (Weeks 7–8)
- Define governance (owners, cadence, versioning) and authoring templates + DoD
- Stand up a simple metrics dashboard (time‑to‑update, duplicates, validation failures)
Outcome: Repeatable workflow with visible performance.
Runbook and Training (Weeks 9–10)
- Create 2–3 micro‑playbooks (Add new error, deprecate feature, propagate change)
- Deliver a 60‑minute hands‑on session
Phase 6 – Retro and Scale (Weeks 11–12)
- Compare outcomes to targets; remove friction
- Choose next scope (another product area or content type)
Roles:
Vocabulary Owner, Ontology Steward, SHACL Validator, Schema Steward, Signal Integrator, Metrics Lead.
Success looks like:
Authors ship updates in ≤30 minutes, ontology compliance is default, and upstream changes surface within 24 hours.
How This KOS Focus Advances Your TechComm Career
Mastering vocabulary/taxonomy→ontology workflows, SKOS/OWL modeling, and SHACL‑based validation moves you from content producer to systems problem‑solver.
Here’s how that translates into career leverage:
- Measurable wins:
- 30–40% faster updates
- Fewer support escalations tied to docs
- Terminology consistency that reduces translation errors, and makes everything make the same sense
- 30–40% faster updates
- More issues caught pre‑publication via validation
Cross‑functional leadership:
- Align terms and fields with Product, Support, Engineering
- Own validation and change protocols across teams
- Portability:
- Skills transfer across stacks (CMS, docs-as-code, bespoke systems)
- Applicable in tech, healthcare, finance, and government, most organisations
- Skills transfer across stacks (CMS, docs-as-code, bespoke systems)
- Career pathways opened:
- Content Operations
- Knowledge Engineering
- Documentation Systems Architect
- Technical Knowledge Manager
- Content Operations
Build evidence that travels with you:
- Portfolio essentials:
- Before/after troubleshooting unit
- Controlled vocabulary snippet with aliases
- Before/after troubleshooting unit
- SKOS/OWL snippet showing concept→class mapping
- Compensation signal:
- Semantic modelling competence underpins automation and AI, leading to higher‑value projects and faster progression into architect/lead roles.
Stay Connected and Keep Learning
Keep the momentum going between my little posts. Subscribe for updates, reinforce your strategy foundations, and add AI‑ready practices that complement your KOS work. Each step up the stack compounds.
- Subscribe to Ignite! for new courses and KOS-focused resources
- Strengthen strategy foundations ahead of graphs with Content Strategy Overview
- Build AI-ready workflows alongside KOS with Structuring Prompts for Technical Communicators
- Prefer a guided foundation in structured authoring? Take DITA Concepts
- Looking for your next role, or hiring?
Candidates
Clients
Consultancy - Prefer hands-on help? Contact Firehead
Next in Firehead’s KOS for modern technical communicators series, I’ll cover the next transition up the stack: moving from ontologies to knowledge graphs. The focus will be on connecting domains, aligning identifiers, and enabling cross‑system queries so search, recommendations, and automation get smarter by design.
Firehead. Visionaries of potential.

