A segue (i/ˈsɛɡweɪ/) is a smooth transition from one topic or section to the next.
In music, segue is a direction to the performer. It means continue (the next section) without a pause. It comes from the Italian "it follows". The term attacca is also used in classical music.
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.