triradius

[ trahy-rey-dee-uh s ]
/ traɪˈreɪ di əs /

noun, plural tri·ra·di·i [trahy-rey-dee-ahy] /traɪˈreɪ diˌaɪ/, tri·ra·di·us·es. Physical Anthropology.

a Y-shaped group of ridges on the palm of the hand at the base of each finger.

Origin of triradius