ground floor is a noun meaning "the floor of a building that is at or nearest to the level of the ground around the building". It carries 2 recorded senses.
the floor of a building that is at or nearest to the level of the ground around the building
becoming part of a venture at the beginning (regarded as position of advantage)
“he got in on the ground floor”
Definitions, synonyms and semantic relations for ground floor come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.