Legato is a form of articulation in which notes are played or sung smoothly and with no intervening silence between them. It is the opposite of staccato, in which the notes are shorter and distinct from one another. Legato is indicated in standard music notation either by the use of the word 'legato' or with a slur, which is a gently curved horizontal line placed above or below the affected notes. The techniques for playing legato differ according to the type of instrument and can take years of practice to master.