1The number eight, used with the native Japanese counting system for counting small objects (e.g. items, sweets).
りんごを八つ買ってきてください。
Please buy eight apples.
テーブルの上にクッキーが八つ並んでいる。
Eight cookies are lined up on the table.
子どもたちは風船を八つ膨らませた。
The children blew up eight balloons.
2A traditional way of saying "eight years old," typically used for a child's age.
うちの娘は今年八つになります。
My daughter turns eight this year.
「お前はいくつだ」「八つだよ」と男の子が答えた。
"How old are you?" "Eight," the boy answered.
3An old term for the time of day roughly corresponding to today's two o'clock (from the pre-modern Japanese hour system); the origin of the word おやつ (afternoon snack).
古い時代には八つ時になると寺の鐘が鳴った。
In olden times, the temple bell would ring at the hour of "yattsu."