• (n. pl.) A group of birds having the bill deeply cleft.
Fis`si·ros'tres noun plural [ New Latin , from Latin fissus (past participle of findere to cleave) + rostrum beak.] (Zoology) A group of birds having the bill deeply cleft. 
The Fissirostres are the wide-gaped tribe of passerine birds. They are characterized by a broad bill, more or less flattened horizontally, and often hooked at the tip, with the mouth very deeply cleft. The upper mandible is not notched. The feet are small and feeble. Most of the species feed on insects, which they catch on the wing, but at least on...
fissirostres A group of birds having the bill, or beak, with a deep cleft.