Pertaining to or consisting of a pair or pairs; divided into two, or having a dual arrangement or order.
Specifically— In botany, regularly dividing by pairs from below upward; two-forked: as, a dichotomous stem. A good example of a dichotomous stem is furnished by the mistletoe. See cut under dichotomy.
In zoology:
Branching by pairs; biramous; bifurcate; forked: as, the dichotomous division of a deer's antlers; the dichotomous foot of a crustacean.
Distichous; bifarious; two-rowed or two-ranked; parted in the middle: as, the dichotomous hairs of a squirrel's tail.
In classification, binary; dual; arranged in two ranks or series; opposed by pairs, as a set of characters, or a number of objects characterized by dichotomization. Also dichotomic.