Etymology
Borrowed from New Latin atonia, from Ancient Greek ἀτονία (atonía, “languor”), from ἄτονος (átonos, “languid”), from ἀ- (a-, “privative”) + τόνος (tónos, “accent”), from τείνω (teínō, “to stretch”).
Definitions & examples from Wiktionary (CC BY-SA 3.0).