gyr·fal·con also ger·fal·con (jûr'fāl'kən, -fôl'-, -fô'-) n. A large falcon (Falco rusticolus) of Arctic regions, having color phases that range from black to gray to white.
[Middle English girfaucoun, from Old French girfaut, gerfaucon : Old High German gīr, vulture + Old French faucon, falcon; see falcon.]
1209, from O.Fr. gerfauc, probably from Frankish, from P.Gmc. *ger (cf. O.H.G. gir "vulture") + L. falco "hawk." Folk etymology connects it with L. gyrus (see gyre) in reference to "circling" in the air.