| 1 | Middle English | faucoun | A peregrine falcon or any other bird of prey... |
| 2 | Old French | falcun | Alternative form of faucon |
| 3 | Late Latin | falco | falcon |
| 4 | Proto-West Germanic | falkō | falcon |
| 5 | Proto-Germanic | falkô | falcon |
| 6 | Proto-Indo-European | pōl- | — |
| 7 | Slovincian | pól | — |
| 8 | Proto-Slavic | polъ | side, flank; half; member of a pair of options →... |
| 9 | Proto-Indo-European | (s)pelH- | to split off, separate; to chop, to separate |