The ultimate A-Z product design glossary

Why a glossary matters

This article is part of our UX design guide. Start there for the big picture.

Product design borrows words from psychology, computer science, graphic design, business strategy, and half a dozen other disciplines. The result? A vocabulary that feels impenetrable to newcomers and inconsistent even among experienced practitioners. This glossary cuts through the jargon with plain-English definitions for the terms you’ll run into most.

A

Accessibility (a11y)

Designing products that work for people with a wide range of abilities — visual, auditory, motor, and cognitive. It’s not an add-on. It’s a fundamental quality of good design. Standards like WCAG 2.1 give you measurable guidelines to aim for.

Affordance

A property of an object or interface element that hints at how it should be used. A raised button affords pressing. Underlined blue text affords clicking. When affordances are clear, users know what to do without being told.

Atomic design

A methodology by Brad Frost that organizes UI components into five levels: atoms (basic elements like buttons and labels), molecules (simple groups like a search bar), organisms (complex sections like a header), templates (page-level layouts), and pages (specific instances with real content). It’s a core concept in building scalable design systems.

C

Card sorting

A research technique where participants organize topics into categories. You use it to inform information architecture, navigation structure, and labeling. Can be open (participants create their own categories) or closed (categories are predefined).

Cognitive load

The total mental effort required to use an interface. Designs that minimize it — through clear hierarchy, familiar patterns, and progressive disclosure — are easier and more pleasant to use. Miller’s Law suggests working memory holds roughly seven items, plus or minus two.

D

Design tokens

Named, platform-agnostic variables storing visual design decisions — colors, spacing, typography, shadows. They bridge design and development by creating a shared language that works across tools, platforms, and frameworks. For a deeper dive into token architecture, see the design systems glossary.

Double diamond

A design process model from the British Design Council. Four phases: Discover (diverge to understand the problem), Define (converge on the right problem), Develop (diverge to explore solutions), and Deliver (converge on the right solution). The two diamonds represent two cycles of divergent and convergent thinking.

E

Empathy map

A collaborative tool capturing what a user says, thinks, does, and feels about an experience. Teams use it during research synthesis to build shared understanding of user needs and motivations.

F

Fitts’s law

The time to reach a target depends on the target’s size and distance. Larger, closer targets are faster to click or tap. This directly informs button sizing, navigation placement, and touch target design. Simple idea, huge impact.

G

Gestalt principles

Perceptual principles describing how we group visual elements. The big ones: proximity (close elements feel related), similarity (similar elements get grouped), continuity (the eye follows smooth paths), and closure (the mind completes incomplete shapes).

H

Heuristic evaluation

An inspection method where evaluators assess an interface against recognized usability principles — most commonly Jakob Nielsen’s 10 Usability Heuristics. It’s fast, cheap, and effective at catching common usability issues without user testing.

I

Information architecture (IA)

The structural design of shared information environments. IA determines how content is organized, labeled, and connected so users can find what they need and understand where they are. Think sitemaps, taxonomies, and navigation models.

J

Journey map

A visual representation of a user’s end-to-end experience with a product or service. It plots actions, touchpoints, emotions, and pain points across stages to reveal opportunities you might otherwise miss.

K

KPI (key performance indicator)

A measurable value showing how effectively a product or team is hitting objectives. In UX, common KPIs include task success rate, time on task, error rate, NPS, and conversion rate. Our guide to measuring UX success covers each of these in depth.

L

Lean UX

An approach that weaves UX design into Agile development through rapid experimentation, lightweight deliverables, and continuous learning over heavy upfront documentation. Core practices: hypothesis-driven design, MVPs, and build-measure-learn cycles.

M

Mental model

A user’s internal picture of how a system works. When the product matches this picture, interactions feel intuitive. When it clashes, confusion and errors follow. Card sorting and contextual inquiry help you uncover what users actually expect.

N

Nielsen’s 10 usability heuristics

Ten general principles for UI design, published by Jakob Nielsen in 1994 — and still widely used:

1. Visibility of system status
2. Match between system and the real world
3. User control and freedom
4. Consistency and standards
5. Error prevention
6. Recognition rather than recall
7. Flexibility and efficiency of use
8. Aesthetic and minimalist design
9. Help users recognize, diagnose, and recover from errors
10. Help and documentation

P

Persona

A fictional, research-based profile representing a segment of your target audience. Personas capture goals, behaviors, pain points, and context to keep teams designing for real user needs instead of assumptions.

Progressive disclosure

Show only the information and options relevant to the current task, then reveal complexity as needed. This keeps cognitive load low and makes interfaces approachable for beginners while still supporting expert workflows.

R

Responsive design

Designing interfaces that adapt gracefully to different screen sizes and devices. Fluid grids, flexible images, CSS media queries — the goal is one product that works well from mobile to desktop without separate implementations.

S

Sprint

A fixed time period — typically one or two weeks — during which a cross-functional team completes a defined set of work. Sprints are the heartbeat of Agile development, structuring the rhythm of design, build, and review.

U

Usability testing

Real users attempt tasks while you watch for difficulties. Tests can be moderated or unmoderated, in-person or remote, qualitative or quantitative. Even five users will reveal the majority of usability issues. I’ve never run a usability test that didn’t surface at least one surprise — the value is hard to overstate.

V

Visual hierarchy

Arranging design elements to signal their order of importance. Your tools: size, color, contrast, spacing, typography weight, and position. Good visual hierarchy guides the eye through the interface in a deliberate sequence.

W

Wireframe

A low-fidelity representation of a screen layout focusing on structure, content placement, and functionality — not visual design. Wireframes are fast to make, easy to iterate, and useful for getting teams aligned on layout before you invest in high-fidelity work.

Z

Zero state (empty state)

The screen users see when there’s no data to display — no messages, no projects, no search results. Well-designed zero states guide users toward their first action and turn a potentially confusing blank screen into an onboarding moment.

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This glossary is a working reference, not an academic one. I’ve kept definitions close to how these terms are actually used in product teams, which sometimes drifts from textbook definitions. As the field moves, new terms will appear and old ones will shift. Bookmark it, pass it around your team, and come back when you hit an unfamiliar term.