suffix
Suffix attached to nouns indicating a time period, range, or group to mean 'within that scope'. Often used in formal or written contexts. Antonym: 外 (がい).
Antonyms: 外
今週内にレポートを提出してください。
Please submit the report within this week.
この問題は私の理解の範囲内です。
This problem is within the scope of my understanding.