each; per piece
Used when specifying a quantity, price, or attribute for each individual item. Common in commercial and instructional contexts.
このリンゴは一個当たり百円です。
These apples are 100 yen each.
一個当たりの重さを量ってください。
Please weigh each piece.
Means 'one piece' without the 'per' nuance; 一個当たり explicitly adds the distributive meaning.
Standard kanji spelling using 当たり.
Common variant with あたり in kana.
Variant using numeral １ instead of 一.
Variant with numeral １ and kana あたり.
Less common variant using 当り.
Rare variant with numeral １ and 当り.
Compound of 一個 (one piece) and 当たり (per, hit). The reading いっこ is a standard counter form of 一個.