Trigonate

a. Zool. [f. as prec. + -ATE².] = prec. adj. 1 and 2.

1815.  Stephens, in Shaw, Gen. Zool., IX. I. 226. Female without the white trigonate spot beneath the chin.

1828.  Stark, Elem. Nat. Hist., II. 203. A[mmothea] Caroliniensis,… back with three trigonate tubercles.