Of persons or things: Most aged, farthest advanced in age. Also absol. quasi-n. Obsolete in general sense: replaced by oldest, adj.

Someone or something that is greatest in some respect. The eldest. Obsolete. rare.

Most, foremost, soonest.

= eldest, adj. 2, esp. designating the first born of several siblings. Also as n.: an oldest sibling, etc.

Oldest, eldest. Cf. greater, adj. 2. Obsolete.

Of a thing, esp. an animal or plant: very old, ancient; venerable.

Used as a postmodifier, usually after a surname, to designate the older or oldest of two or more members of the same family. Cf. senior, adj. 1a…