001 · A daily design lexicon

Lemma.

Learn the language of product and design — one term a day. Calm, considered, and quietly habit-forming.

A/B Testing▪Accessibility▪Accordion▪Affordance▪Alpha (Transparency)▪Asymmetry▪Atomic Design▪Badge▪Border Radius▪Breadcrumb▪Breakpoint▪Button▪Call to Action▪Card▪Card Sorting▪Carousel▪Churn▪Cognitive Load▪Color Space▪Color Theory▪Color-Only State▪Component▪Confirmation Dialog▪Contrast▪Conversion Rate▪Dark Mode▪Design Critique▪Design System▪Design Thinking▪Design Token▪Double Diamond▪Duration▪Easing▪Empty State▪Error State▪Feedback▪Fidelity▪Flat Design▪Focus State▪Front-Loading▪Funnel▪Gestalt Principles▪Gradient▪Grid System▪Handoff▪Heatmap▪Heuristic Evaluation▪Hover State▪Information Architecture▪Input▪Jobs to Be Done▪Journey Map▪Kerning▪Layout Shift▪Leading▪Line Length▪Mental Model▪Microcopy▪Microinteraction▪Minimum Viable Product▪Modal▪Moodboard▪Navigation▪Net Promoter Score▪North Star Metric▪Onboarding▪Optical Center▪Optimistic Update▪Pattern Library▪Persona▪Placeholder▪Popover▪Progressive Disclosure▪Prototype▪Reduced Motion▪Responsive Design▪Retention▪Saturation▪Screen Reader▪Semantic HTML▪Sentence Case▪Session Recording▪Sidebar▪Signifier▪Skeleton▪Skeuomorphism▪Skip Link▪Source of Truth▪Stagger▪Stroke Weight▪Style Guide▪Tabs▪Tag▪Toast▪Tooltip▪Touch Target▪Tracking▪Type Scale▪Typography▪Usability▪Usability Testing▪User Flow▪User Research▪Value Proposition▪Visual Hierarchy▪Visual Language▪Voice & Tone▪Wayfinding▪WCAG▪White Space▪Widows & Orphans▪Wireframe▪A/B Testing▪Accessibility▪Accordion▪Affordance▪Alpha (Transparency)▪Asymmetry▪Atomic Design▪Badge▪Border Radius▪Breadcrumb▪Breakpoint▪Button▪Call to Action▪Card▪Card Sorting▪Carousel▪Churn▪Cognitive Load▪Color Space▪Color Theory▪Color-Only State▪Component▪Confirmation Dialog▪Contrast▪Conversion Rate▪Dark Mode▪Design Critique▪Design System▪Design Thinking▪Design Token▪Double Diamond▪Duration▪Easing▪Empty State▪Error State▪Feedback▪Fidelity▪Flat Design▪Focus State▪Front-Loading▪Funnel▪Gestalt Principles▪Gradient▪Grid System▪Handoff▪Heatmap▪Heuristic Evaluation▪Hover State▪Information Architecture▪Input▪Jobs to Be Done▪Journey Map▪Kerning▪Layout Shift▪Leading▪Line Length▪Mental Model▪Microcopy▪Microinteraction▪Minimum Viable Product▪Modal▪Moodboard▪Navigation▪Net Promoter Score▪North Star Metric▪Onboarding▪Optical Center▪Optimistic Update▪Pattern Library▪Persona▪Placeholder▪Popover▪Progressive Disclosure▪Prototype▪Reduced Motion▪Responsive Design▪Retention▪Saturation▪Screen Reader▪Semantic HTML▪Sentence Case▪Session Recording▪Sidebar▪Signifier▪Skeleton▪Skeuomorphism▪Skip Link▪Source of Truth▪Stagger▪Stroke Weight▪Style Guide▪Tabs▪Tag▪Toast▪Tooltip▪Touch Target▪Tracking▪Type Scale▪Typography▪Usability▪Usability Testing▪User Flow▪User Research▪Value Proposition▪Visual Hierarchy▪Visual Language▪Voice & Tone▪Wayfinding▪WCAG▪White Space▪Widows & Orphans▪Wireframe▪

002 · Today’s termNo. 067

Visual Design

Optical Center

The optical center is where something looks centered to the eye, which is often slightly different from where it sits mathematically. Our perception, not the ruler, decides whether placement feels balanced.

Example

A play button drawn as a triangle inside a circle looks left-heavy when centered by coordinates, because the shape's visual mass sits on the left. Nudging the triangle slightly right makes it finally look centered.

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