- [noun] a curved shape in the vertical plane that spans an opening
- [noun] a curved bony structure supporting or enclosing organs (especially arches of the feet)
- [noun] a passageway under an arch
- [noun] (architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it
- [verb] form an arch or curve; "her back arches"; "her hips curve nicely"
Synonyms: curve, arc
- [adjective] (of persons) highest in rank or authority or office; "his arch rival"
- [adjective] (used of behavior or attitude) characteristic of those who treat others with condescension
Synonyms: condescending, patronizing, patronising
- [adjective] expert in skulduggery; "an arch criminal"