Fork

From WikiChess

A fork is a powerful move that threatens multiple pieces. The attacking piece (often a knight, sometimes a bishop) moves into a position where it can capture multiple pieces of the opposing color. If one of those pieces is a king, it is a "royal fork" and gives check. The opposing player is forced to respond by protecting one of the pieces, leaving the other open for capture on the next move.

It is sometimes referred to as a "split move."