The Collaborative International Dictionary of English v.0.48:
Flycatcher \Fly"catch`er\, n. (Zool.)
One of numerous species of birds that feed upon insects,
which they take on the wing.
Note: The true flycatchers of the Old World are Oscines, and
belong to the family Muscicapid[ae], as the spotted
flycatcher (Muscicapa grisola). The American
flycatchers, or tyrant flycatchers, are Clamatores, and
belong to the family Tyrannid[ae], as the kingbird,
pewee, crested flycatcher (Myiarchus crinitus), and
the vermilion flycatcher or churinche (Pyrocephalus
rubineus). Certain American flycatching warblers of
the family Sylvicolid[ae] are also called
flycatchers, as the Canadian flycatcher (Sylvania
Canadensis), and the hooded flycatcher (S. mitrata).
See Tyrant flycatcher.