also: ふたりづつ
adverb, noun which may take the genitive case particle 'no'
two by two; in pairs; as a couple
Describes doing something in groups of two, or distributing items two per person/unit.
The students walked in pairs.
Please hand out two copies of this handout to each pair.
Standard spelling using ずつ.
Variant spelling using づつ; less common but still encountered.
Compound of 二人 (ふたり, 'two people') and the distributive suffix ずつ ('each', 'at a time').