Slur

A slur is a symbol in western musical notation indicating that the notes it embraces are to be played legato (smoothly). In music for boweded string instruments, it indicates the notes should be played in one bow; in music for wind instruments, that the notes should be played in one breath. In vocal music, slurs are usually used to mark notes which are sung to a single syllable.

A slur is denoted with a curved line generally placed over the notes if the stems point downward, and under them if the stems point upwards:

A similar symbol is used to indicate ties, which join notes of the same pitch.