Added 9 October 2026 eldest /ˈɛldɪst/ noun Categories: PeopleUncommon Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about eldest at Wordnik → Where our words come from → The offspring who came first in the order of birth. adjective First in order of birth. the firstborn child Related Words: firstfirstbornmostbigelderfirst-bornoldestseniorelderlytaibiggestgreatest Back to today's word