| 1 | English | flat | Having no variations in height; Without... |
| 2 | Scots | flet | inner part of a house |
| 3 | Middle English | flet | the floor, ground; a dwelling, habitation, house,... |
| 4 | Old English | flet | the floor, ground; a dwelling, habitation, house,... |
| 5 | Proto-Germanic | flatją | a level surface; level ground; the floor of a... |
| 6 | Proto-Germanic | flataz | flat |
| 7 | Proto-Indo-European | plÁt- | — |