overwrite edit

In an overwrite edit, one or more source clips overwrite any clips in the primary storyline or a selected storyline, starting at a range selection start point or at the skimmer or playhead position. No clip items are rippled forward, so the duration of your project remains the same.

An illustration showing a clip overwriting parts of two other clips

Overwriting is purely duration-based and works on range selections only, irrespective of clip boundaries.