a. and sb. Ornith. [f. L. terti-us third + -AL.] a. adj. Of or pertaining to the third rank or row of quill- or flight-feathers in the wing of a bird. b. sb. A flight-feather of the third row; sometimes erroneously applied to secondaries on the elbow-joint. See TERTIARY B. 3.
1836. Swainson, Nat. Hist. Birds, I. I. iii. 81. They [Quills] … form three divisions, distinguished as the primaries, the secondaries, and the tertials…. The tertials … have their origin from the humerus.
1842. Brande, Dict. Sc., etc., Tertials.
1874. Coues, Birds N. W., 665. The color of the mantle extends to the tips of the tertials.
