A separation or division into two; a distinction that results in such a division. / Such a division involving apparently incompatible or opposite principles; a duality.

plural of dichotomy

(botany) A branching in which the main axis appears to divide dichotomously at the apex but is in reality suppressed, the growth being continued by lateral branches (as in the dichasium).

(software engineering) The tendency for high-level programming languages to fall into one of two groups: systems programming languages and scripting languages.

plural of false dichotomy