In musical notation the Italian word legato (literally meaning "tied together") indicates that musical notes are played or sung smoothly. That is, in transitioning from note to note, there should be no intervening silence. Legato technique is required for slurred performance, but unlike slurring (as that term is interpreted for some instruments), legato does not forbid rearticulation. In standard notation legato is indicated either with the word legato itself, or by a curved line over or under the notes that are to be joined in one legato group. Legato, like staccato, is a kind of articulation. There is an intermediate articulation called either mezzo staccato or non-legato.
In guitar playing (apart from classical guitar) legato usually refers to slurred notes, such as hammer-ons and pull-offs. Use of legato technique with electric guitar will generally require playing notes that are close and on the same string, following the first note with others that are played by the techniques just mentioned. Many electric-guitar virtuosos, usually shredders, are well-versed in this technique, as it allows for rapid and also "clean" runs. Multiple hammer-ons and pull-offs together are sometimes also referred to colloquially as "rolls," a reference to the fluid sound of the technique. A rapid series of hammer-ons and pull-offs between a single pair of notes is called a trill. When playing legato on guitar, it is common for the musician to play more notes within a beat than the stated timing, i.e. playing 5 or 7 sixteenth-notes (as opposed to 4) against a quarter-note. This gives the passage an unusual timing and when played slowly an unusual sound. However, this is less noticeable by ear when played fast, as legato usually is. There is a fine line between what is legato and what is two hand finger tapping, in some cases making the two techniques harder to distinguish by ear. Generally, Legato is used to add a more fluid, smooth sound to the passage being played.
Some guitarists widely noted for their skill with legato include Tony MacAlpine, Shawn Lane, Greg Howe, Richie Kotzen, Trace Bundy, Joe Stump, Jimi Hendrix, George Lynch, Allan Holdsworth, Randy Rhoads, Marty Friedman, Joe Satriani, Eddie Van Halen, Michael Angelo Batio, Yngwie J. Malmsteen, John Petrucci, Buckethead, Dave Murray, Adrian Smith, Steve Vai, Mark Tremonti, Chris Poland, Dimebag Darrell and Bill Connors.
In music for classical stringed instruments, legato often refers to notes played with a full bow, that are played with minimal silence between notes. This may be achieved through controlled wrist movements of the bowing hand, often masked or enhanced with vibrato. Such a legato style of playing may also be associated with the use of portamento.
In synthesizers legato is a variation of monophonic operation. In contrast to monophonic mode where every new note restarts the ADSR envelopes, in legato mode they are not if the previous note remains depressed when the new note is played. This causes the initial transient from the attack and decay phases to sound only once and the ADSR's to remain at sustain stage for the whole sequence of notes until the final note is released. Janne Warmen of Metal band Children Of Bodom uses legato quite often in his solos.