noun
ten years old; age 10
Used to state that someone or something is ten years of age. The reading じっさい is a common colloquial variant.
息子は今年で十歳になります。
My son will be ten years old this year.
十歳の誕生日に自転車をもらった。
I got a bicycle for my tenth birthday.
十代 means 'teenage years' (10–19), while 十歳 specifically means 'ten years old'.
Compound of 十 (ten) and 歳 (years of age). The reading じゅっさい is a regular sound shift from じっさい, which is now considered a colloquial variant.