define baby
baby noun [C]. A1 a very âyoung âchild, âespecially one that has not âyet âbegun to âwalk or âtalk: a ânewborn baby a six-week-old baby a baby âboy baby âclothes baby âfood Sandra had a baby (= gave âbirth to it) on 29 May. Owen is the baby (= the âyoungest âperson) of the âfamily. A2 a very âyoung âanimal: a baby âelephant/âmonkey âº disapproving an âadult or âespecially an âolder âchild who is âcrying or âbehaving like a âchild: It didn't âhurt that much-don't be such a baby!