The term is derived from Italian segue, "follows".
For written music it implies a transition from one section to the next without any break. In improvisation, it is often used for transitions created as a part of the performance, leading from one section to another.
In live performance, a segue can occur during a jam session, where the improvisation of the end of one song progresses into a new song. Segues can even occur between groups of musicians during live performance. For example, as one band finishes its set, members of the following act replace members of the first band one by one, until a complete band swap occurs.
In recorded music, a segue is a seamless transition between one song and another. The effect is often achieved through beatmatching, especially on dance and disco recordings, or through arrangements that create the effect of a musical suite, a classical style also used in many progressive rock recordings. The songs may further contain a lyrical connection or overall theme as well. With breakless joins of the elements in his albums Frank Zappa made extensive use of the segue technique. This was first used in 1966 on Zappa's Freak Out!, and a year later on the Beatles' Sgt. Pepper's Lonely Hearts Club Band.
In some Brazilian musical styles, where it is called "emendar" ("to splice"), in particular in Samba and Forró Pé de Serra, it is very commonly used in live performances, creating sets that usually last around 20 minutes but can sometimes take more than an hour, switching seamlessly between different songs. The larger rhythm groups of bands, with up to ten percussionists in Samba for example, facilitate the switching of one song to another, as the percussionists keep the rhythm or beat going while the pitch instruments prepare the harmonical transition to the next song, often with just one pitch instrument leading this transition. In Forró trios, where the only pitch instrument (apart from the voice) is the accordion (which plays together with two percussionists), the accordionist usually "puxa" ("pulls") the next song as soon as the previous has finished.
Some album notations distinguish track listings through the use of symbols, such as a >, ->, or / to indicate songs that flow seamlessly. The alternative rock band Failure separates these musical transitions into individual tracks, which are simply given numerical distinctions such as Segue 1. This system began with their 1996 album Fantastic Planet.
In audio/visual media, a segue is smooth transition from one scene or topic to another. A segue allows the director or show host to naturally proceed from one scene or topic to another without jarring the audience. A good segue makes the transition look natural and effortless.