- division into two parts, kinds, etc.; subdivision into halves or pairs.
- division into two mutually exclusive, opposed, or contradictory groups: a dichotomy between thought and action.
- a mode of branching by constant forking, as in some stems, in veins of leaves, etc.
- the phase of the moon or of an inferior planet when half of its disk is visible.
- division into two parts or classifications, esp when they are sharply distinguished or opposed
- the division of a class into two mutually exclusive subclasses
- a simple method of branching by repeated division into two equal parts
- the phase of the moon, Venus, or Mercury when half of the disc is visible
