We found one dictionary that defines the word let someone in on the ground floor:

Miscellaneous (1 matching dictionary)

1. let someone in on the ground floor: Idioms

▸ Words similar to let someone in on the ground floor ▸ Usage examples for let someone in on the ground floor ▸ Idioms related to let someone in on the ground floor ▸ Wikipedia articles (New!) ▸ Words that often appear near let someone in on the ground floor ▸ Rhymes of let someone in on the ground floor ▸ Invented words related to let someone in on the ground floor