Meaning

noun past times (especially in the phrase `in days of old')

adjective (used especially of persons) having lived for a relatively long time or attained a specific age

adjective of long duration; not new

originInherited from Middle English old, oold, from Old English ald, eald (“old, aged, ancient, antique, primeval”), from Proto-West Germanic *ald, from Proto-Germanic *aldaz (“grown-up”), originally a participle form, from Proto-Indo-European *h₂eltós (“grown, tall, big”). Cognates Cognate with Scots aald, auld (“old”), Yola yola, yolaw, yold, yole (“old”), North Frisian ool, ual, uuil, uul, üülj…

Etymology from Wiktionary, CC BY-SA 3.0