ˌground ˈfloor BrE AmE noun
1 . [countable] especially British English the floor of a building that is at ground level SYN first floor American English :
a ground floor flat
The dining room is on the ground floor.
⇨ ↑ floor 1 (3)
2 . be/get in on the ground floor to become involved in a plan, business activity etc from the beginning