1. to come between parties in a dispute in order to help resolve it
2. to interrupt or interfere with something in progress
3. to occur between two events or points in time

Examples

• The teacher had to intervene when the students started arguing.
• The United Nations decided to intervene in the conflict.
• She intervened before the situation got worse.
• Several years intervened between his first and second novels.
• The police intervened to stop the fight.
• Bad weather intervened and delayed our plans.
• Parents should intervene if their child is being bullied.