Moirai was the Greek collective name of the Fates (called also Parcae by the Romans). According to Hesiod, they were the daughters of Zeus and Themis, and were named as Clotho, Lachesis and Atropos. Their name works out as 'allotters', from meiromai, 'to have a share', a fitting sense for the Fates who portioned out a person's life.

Homer usually wrote of one single Moira, seeing her as a personification of fate. (In his Iliad she is shown as spinning out the thread of a man's life at his birth.) Her name is not, however, the origin of the modern girl's name Moira: this is a version of an Irish name that is the equivalent of Mary.