When two things overlap, they cover the same space or happen at the same time. Picture two circles drawn on paper so that part of each circle sits on top of the other: that shared area in the middle is the overlap. Your thumb and fingers overlap when you make a fist. Roof shingles overlap like fish scales so rain can't leak through.

The word also describes when schedules coincide. If soccer practice and piano lessons overlap, they happen during the same hours, creating a conflict. Two friends might discover their interests overlap when they both love astronomy and building model rockets.

In conversations, people’s ideas can overlap. During a class discussion about your town’s new park, one student might talk about adding more trees while another suggests building shaded picnic areas. Their topics overlap because both are about making the park more comfortable for visitors.

The noun form describes the shared part itself: “There's a two-hour overlap between their shifts” or “Scientists study the overlap between biology and chemistry.”