alias (n.) Look up alias at Dictionary.com
"assumed name," c. 1600, from alias (adv.).
alias (adv.) Look up alias at Dictionary.com
mid-15c., "otherwise called," from Latin alias (adv.) "at another time," in Late Latin also "in another way, under other circumstances," from alius "another, other, different," from PIE root *al- (1) "beyond," which is the source also of English else.