ground floor
noun🔊/ˌɡraʊnd ˈflɔː(r)/
🔊/ˌɡraʊnd ˈflɔːr/
(British English) (North American English first floor)
Idioms the floor of a building that is at the same level as the ground outside 底层，底楼，一楼（建筑物与外面地面相平的一层）
Idioms
be/get in on the ground floor
to become involved in a plan, project, etc. at the beginning 在开始时参与