Extension
- Agricultural extension
- Axiom of extensionality
- Browser extension
- Continuing education
- Cooperative State Research, Education, and Extension Service
- Extended (Solar Fields album)
- Extensible cardinal
- Extension (Clare Fischer album)
- Extension (George Braith album)
- Extension (anatomy)
- Extension (geology)
- Extension (metaphysics)
- Extension (model theory)
- Extension (music)
- Extension (predicate logic)
- Extension (proof theory)
- Extension (semantics)
- Extension (simplicial set)
- Extension (telephone)
- Extension by definitions
- Extension cord
- Extension of a function
- Extension of a polyhedron
- Extension, British Columbia
- Extension, Louisiana
- Extensional definition
- Extensionality
- Extensions (Ahmad Jamal album)
- Extensions (Dave Holland album)
- Extensions (McCoy Tyner album)
- Extensions (The Manhattan Transfer album)
- Extensive (disambiguation)
- Exterior algebra
- Eyelash extensions
- Field extension
- Filename extension
- Group extension
- Hair extensions
- Homotopy extension property
- Kolmogorov extension theorem
- Kylie Minogue
- Linear extension
- Melanocortin 1 receptor
- Mystic Moods Orchestra
- Plug-in (computing)
- Renovation
- Sheaf extension
- Tietze extension theorem
- Whitney extension theorem