周岁

Traditional (Taiwan): 週歲

On the HSK 7-9 vocabulary list, at CEFR level C1.

zhōusuì ㄓㄡ ㄙㄨㄟˋ

    • one full year (e.g. on child's first birthday)

Character by character

Classifiers (measure words)

周岁 itself can also be a classifier

Sources