歳・才|さいsai[1]atamadaka (head-high)

1. counter... years old; age (of) ...
   「１７歳さいの時ときスクーナー船せんで地中ちちゅう海かいを航海こうかいしたわ」彼女かのじょはゆっくりと注意ちゅうい深ふかく言ゆう。↗

   "I sailed around the Mediterranean in a schooner when I was seventeen," she recited slowly and carefully.

• Related年頃としごろNeutralAn approximate or marriageable age, as in 「年頃の娘」; it is not a counting unit — count age with 「歳」.
• Related年端としはWrittenWritten/formal prose word for age, as in 「年端も行かない」; mostly used in negatives.

Count age with the counter 「歳」, as in 「二十歳」「三歳」; it is also written 「才」. For an approximate age, say 「年頃」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. （サイ）年齢ねんれいを数かぞえる助数詞じょすうし。