Translation guide
The English word "baby" covers a wide range of meanings, from a very young child to terms of endearment and slang. This guide breaks down the most useful Japanese equivalents for English-speaking learners, organized by intended meaning.
Referring to a human baby, from newborn to around 2 years old.
The most common and affectionate word for a baby. Safe to use in almost any context.
赤ちゃんが泣いている。
The baby is crying.
彼女は赤ちゃんを抱っこしている。
She is holding a baby.
Also means baby, but slightly more matter-of-fact or literary than 赤ちゃん. Often used in written descriptions.
赤ん坊の世話は大変だ。
Taking care of a baby is tough.
Formal/medical term for an infant (under 1 year old). Used in official documents or healthcare contexts.
乳児死亡率は低下している。
The infant mortality rate is declining.
Referring to a baby still in the womb.
Commonly used for an unborn baby as well, especially in casual conversation.
お腹の赤ちゃんが動いた。
The baby in my belly moved.
Medical/biological term for a fetus. Not used in everyday speech.
Calling a romantic partner "baby" as a pet name.
Japanese doesn't have a direct equivalent of "baby" as a romantic pet name. Instead, use the person's name with an affectionate suffix like ちゃん (for girls/women or cute nicknames) or くん (for boys/men), or create a nickname. Direct translation would sound very strange.
Never translate "baby" literally as 赤ちゃん for a romantic partner; it would be interpreted as an actual infant.
まいちゃん、大好きだよ。
I love you, baby. (to a girlfriend named Mai)
たけるくん、こっち来て。
Come here, baby. (to a boyfriend named Takeru)
Loanword from "darling". Used by some couples, but can sound cheesy or old-fashioned. More common in media than real life.
Calling someone the "baby" of a family, team, etc.
Means the youngest child in a family. Can be extended metaphorically to the youngest member of a group.
彼は家族の末っ子だ。
He's the baby of the family.
チームで一番の末っ子的存在です。
He's like the baby of the team.
Literally "the lowest/youngest". Used for age ranking in a group.
彼が兄弟の中で一番下です。
He's the baby among his siblings.
Calling someone a "baby" because they are acting childish.
Literally "like a baby". Used to tease someone for being childish.
そんなことで泣くなんて、赤ちゃんみたいだね。
Crying over something like that? You're such a baby.
Means "childish". A more direct way to describe immature behavior.
彼の態度は子どもっぽい。
His attitude is so babyish.
Referring to a project or idea as one's "baby".
Literally "like one's own child". The most natural way to express this metaphor in Japanese.
このプロジェクトは私にとって自分の子どものようなものです。
This project is my baby.
Means "one's other self" or "alter ego". Can be used for a creation that embodies oneself, but less common for casual projects.
この作品は私の分身だ。
This work is my baby.
Calling a partner 赤ちゃん (baby) will be understood as referring to an actual infant, not as a term of endearment. Use their name with an affectionate suffix instead.
ねえ、ゆうこちゃん。
Hey, baby. (to Yuko)
Both mean "baby," but 赤ちゃん is warmer and more common in speech. 赤ん坊 is slightly more detached and often appears in writing or formal descriptions. For everyday use, stick with 赤ちゃん.
The fetus is developing normally.
ダーリン、今日は早く帰ってきてね。
Darling, come home early today.