also: ひとつづつ
adverb, noun which may take the genitive case particle 'no'
one by one; one each; one at a time
Used when items are handled individually, distributed one per person/thing, or done sequentially.
See also: ずつ
I handed out the snacks one by one.
Let's solve the problems one at a time.
Variant spelling with づつ; historically common but now less standard.
Rare kanji form using 宛; not commonly used.
Compound of 一つ (one) and the distributive suffix ずつ (each).