aye (interj.) Look up aye at Dictionary.com
"assent," 1570s, of unknown origin, perhaps a variant of I, meaning "I assent;" or an alteration of Middle English yai "yes" (see yea), or from aye (adv.) "always, ever."
aye (adv.) Look up aye at Dictionary.com
"always, ever," c.1200, from Old Norse ei "ever" (cognate with Old English a "always, ever"), from PIE *aiw- "vital force, life, long life, eternity" (cognates: Greek aion "age, eternity," Latin aevum "space of time;" see eon).