noun, plural cris·sa [kris-uh] /ˈkrɪs ə/. Ornithology.
Origin of crissum
Examples from the Web for crissum
Below, pale yellowish wood-brown, straw-yellow on abdomen and crissum.
Below grayish buff rapidly fading when older to a greenish gray; abdomen and crissum pale straw-yellow.
The rump is also much more yellow (less green) and the crissum is more yellow (less orange).
Below, greenish buff paler and yellower on abdomen and crissum.
The mature male is purplish-gray below, with a tendency to whitening on the throat, belly and crissum.Nests and Eggs of Birds of The United States|Thomas G. Gentry