noun
one dose; one installment
Refers to a single portion of something that is taken or paid in parts, such as medicine, payments, or serialized content.
この薬は一回分ずつ包装されています。
This medicine is packaged in single doses.
分割払いの一回分を今日支払った。
I paid one installment of the installment plan today.
分 is a suffix meaning 'portion' or 'amount for'. 一回分 combines it with 一回 to mean 'one-time portion'.
Compound of 一回 (one time) and 分 (portion, amount).