To reorganize or rearrange a group or groups, often after a setback or disruption. After the initial attack, the soldiers had to regroup before launching a counteroffensive.
To come together again in a group after being dispersed. The team decided to regroup at the cafe after the meeting was unexpectedly canceled.
To change one's strategy or approach, often in response to new information or circumstances. After the unexpected results, the marketing team had to regroup and come up with a new plan.
In arithmetic, to shift digits between place values while performing addition or subtraction, often referred to as carrying or borrowing. To subtract 52 − 28 correctly, you first regroup by borrowing one ten from the tens column.