[count] 1 a : a very young child
▪ She had the baby yesterday. = She gave birth to the baby yesterday. ▪ Are you expecting a baby? [=are you pregnant?] ▪ I hear the baby crying. ▪ The baby is just learning to crawl. — often used before another noun ▪ a baby girl/boy ▪ baby clothes ▪ baby pictures ▪ a baby monitor ▪ (US) I gave my sister a baby shower. [=a party at which gifts are given to a woman who is pregnant] ▪ She has a real baby face. [=a face that resembles the face of a baby; a face that looks young and innocent]
b : a very young animal
▪ a bird and its babies — often used before another noun ▪ a baby bird ▪ a baby deer 2 a : the youngest member of a group
▪ My sister is the baby of the family. — often used before another noun ▪ my baby sister
b : someone who is young in comparison with others
▪ “Only 32? Oh, you're just a baby!”
c : someone who behaves like a child ; especially : someone who is afraid or who complains a lot
▪ When it comes to getting shots, I'm a real baby. ▪ Don't be such a baby—you'll get your turn. 3 slang a : a lover or sweetheart
▪ Nothing's gone right since my baby went away. ◊This sense of baby is common in song lyrics.
b — used as an informal way of addressing a lover, friend, etc. — used especially by men to address women and by women to address men ▪ I missed you, baby. ◊This sense of baby is sometimes used in a very informal way by men to address an attractive woman.
▪ Hey baby, nice car! Using baby to address someone you do not know well may cause offense. 4 : something that someone has created and developed with special personal attention or interest
▪ This project is my baby.