Translation guide
In Japanese, the word for 'infant' depends on the child's age and the context. The most common general term is 赤ちゃん (akachan) for babies, while more formal or medical terms like 乳児 (nyūji) are used in specific situations.
To refer to a baby or very young child in everyday, warm contexts.
The most common and affectionate word for a baby. Used by everyone, from parents to strangers.
The baby is crying.
What a cute baby!
Also means baby, slightly more colloquial or old-fashioned than 赤ちゃん. Often used in storytelling or casual speech.
To refer to an infant in medical, official, or formal contexts, specifically a child under one year old.
Formal/medical term for an infant (under 1 year). Used in healthcare, legal documents, and statistics.
To refer to a newborn baby, especially in the first month of life.
To refer to a child in the early stages of life, often still a baby or toddler.
Formal term for an infant or toddler (usually 1-6 years, but can include younger). Used in education and legal contexts.
赤ちゃん is the everyday word for a baby, used affectionately. 乳児 is a formal/medical term for an infant under 1 year. 新生児 specifically means a newborn (first 4 weeks). Use 赤ちゃん in casual conversation, and the others in official or medical contexts.
The English loanword インファント is not commonly used in Japanese. Stick to native Japanese terms.
The baby is sleeping peacefully.
I'm going for the infant's health check-up.
The infant mortality rate is declining.
Medical/formal term for a newborn (up to about 4 weeks). Used in hospitals and official records.
Newborns spend most of the day sleeping.
A descriptive phrase meaning 'newborn baby', used in everyday conversation.
A newborn baby is very small.
I bought a picture book for infants/toddlers.
A general phrase meaning 'small child', often used for infants and toddlers in everyday speech.
Small children are playing in the park.