Definition of "Arch" :

noun: (architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it

noun: a passageway under a curved masonry construction

"They built a triumphal arch to memorialize their victory."

noun: a curved bony structure supporting or enclosing organs (especially the inner sides of the feet)

noun: a curved shape in the vertical plane that spans an opening

verb: form an arch or curve

"Her back arches."

adjective: naughtily or annoyingly playful

adjective: (used of behavior or attitude) characteristic of those who treat others with condescension