/ ɑːtʃ; NAmE ɑːrtʃ/ noun , verb , adjective
■ noun
1.
a curved structure that supports the weight of sth above it, such as a bridge or the upper part of a building
2.
a structure with a curved top that is supported by straight sides, sometimes forming an entrance or built as a monument :
Go through the arch and follow the path.
Marble Arch is a famous London landmark.
3.
the raised part of the foot formed by a curved section of bones
—picture at body
4.
anything that forms a curved shape at the top :
the delicate arch of her eyebrows
■ verb
1.
if you arch part of your body, or if it arches , it moves and forms a curved shape :
[ vn ]
The cat arched its back and hissed.
[also v ]
2.
[ v ] to be in a curved line or shape across or over sth :
Tall trees arched over the path.
■ adjective
[ usually before noun ] (often disapproving ) seeming amused because you know more about a situation than other people
an arch tone of voice
► arch·ly adverb :
'Guess what?' she said archly.
••
WORD ORIGIN
noun and verb Middle English : from Old French arche , based on Latin arcus bow.
adjective mid 17th cent.: from arch- , by association with the sense rogue in combinations such as arch-scoundrel .