From Middle English mot, from Old English mot ("grain of sand; mote; atom"), but of uncertain ultimate origin. Sometimes linked to Spanish mota ("speck") and English mud.
Compare West Frisian mot, Dutch mot, Norwegian mutt.
From Middle English moten, from Old English mōtan ("to be allowed, be able to, have the opportunity to, be compelled to, may, must"), from Proto-Germanic *mōtaną ("to be able to, have to, be delegated"), from Proto-Indo-European *med- ("to acquire, possess, be in charge of"). Cognate with Dutch moeten ("to have to, must"), German müssen ("to have to, must"), Ancient Greek μέδω ("to prevail, dominate, rule over"). Related to empty.