A slur is a symbol in Western musical notation indicating that the notes it embraces are to be played without separation (that is, with legato articulation). 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.
The example below shows two measures in 6
8 with a slur for each measure:
Slurs mean different things for different instruments:
A slur can be extended over many notes, sometimes encompassing several bars. In extreme cases, composers are known to write slurs which are near-impossible to achieve; in that case the composer wishes to emphasise that the notes should be performed with as much legato as possible.