In-sĕs′/sor, n.

n.; pl. IN′/SĔS-SŌ′RĒS. [Lat. insessor, from insidere, to sit in or upon, from prefix in and sedere, to sit.] (Ornith.) One of an order of birds whose feet are formed for perching or climbing on trees. They are generally of small size, and without very marked characters. The order includes most of the common singing birds, the perchers, the Passeres, &c.