In chemistry, a moiety is a specific segment of a molecule. For example, aniline has a phenyl and an amino moiety. Ethidium bromide has both these.

In anthropology, moiety is a term used to describe each descent group in a culture which is divided exactly into two descent groups. Caesar uses the term moiety in William Shakespeare's Antony and Cleopatra after he learns of the death of Antony:

The breaking of so great a thing should make

A greater crack. The round world

Should have shook lions into civil streets

And citizens to their dens. The death of Antony

Is not a single doom; in the name lay

A moiety of the world.

Caesar's message symbolizes the gravity of Antony's death, as it represented the triumph of Rome—and of Western Civilization—over Cleopatra and Egypt.