once or twice; repeatedly
Used adverbially to indicate that something happens a few times, not necessarily many. Often appears in the pattern 一再ならず (more than once).
His unexcused absences happened more than once.
This issue has been discussed repeatedly.
Compound of 一 (one) and 再 (again), literally 'one or two times'. The reading いっさい is a regular on'yomi combination.