The genus Falco was introduced in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae.[7] The type species is the Eurasian hobby (Falco subbuteo).[8] The genus name Falco is Late Latin meaning a "falcon" from falx, falcis, meaning "a sickle", referring to the claws of the bird.[9][10] In Middle English and Old French, the title faucon refers generically to several captive raptor species.[11]

The traditional term for a male falcon is tercel (British spelling) or tiercel (American spelling), from the Latin tertius (third) because of the belief that only one in three eggs hatched a male bird. Some sources give the etymology as deriving from the fact that a male falcon is about one-third smaller than a female[12][13][14] (Old French: tiercelet). A falcon chick, especially one reared for falconry, still in its downy stage, is known as an eyas[15][16] (sometimes spelled eyass). The word arose by mistaken division of Old French un niais, from Latin presumed nidiscus (nestling) from nidus (nest). The technique of hunting with trained captive birds of prey is known as falconry.

Compared to other birds of prey, the fossil record of the falcons is not well distributed in time. The oldest fossils tentatively assigned to this genus are from the Late Miocene, less than 10 million years ago.[citation needed] This coincides with a period in which many modern genera of birds became recognizable in the fossil record. The falcon lineage may, however, be somewhat older than this,[citation needed] and given the distribution of fossil and living Falco taxa, is probably of North American, African, or possibly Middle Eastern or European origin. Falcons are not closely related to other birds of prey, and their nearest relatives are parrots and songbirds