Meaning

noun (biology) the process of decay caused by bacterial or fungal action

verb break down

verb become physically weaker

originFrom Middle English rotynge (“rotting”), from Old English rotung; equivalent to rot + -ing. Conflated with Middle English rotende, present participle of roten (“to rot”), from Old English rotiende, present participle of rotian (“to rot”).

Etymology from Wiktionary, CC BY-SA 3.0