Section of track which curves 180°.

a sequence of chords that usually occurs at the end of a musical phrase

A sequence of chords, or the portion of a tune that they occupy, that forms a cadence at the end of a section of a tune, definitively establishes the tonic key and leads back to the opening chord of the next section, or to the top. Typically the turnaround chords are I - VI - II - V, with half a measure apiece. With possible substitutions and alterations, the variations are infinite. There are also entirely different progressions possible. If the opening chord of the next section is not a I chord, the turnaround must be suitable. Learning to negotiate turnarounds is essential to making a coherent solo. It's often effective to play a phrase that starts partway through a turnaround and continues past the beginning of the next section.

A short chord progression usually within the last two bars of a chorus (chord progression) used to return back to the top of the tune.

An additional section of driveway where cars can be turned around.

In jazz, a turnaround is a passage at the end of a section which leads to the next section. This next section is most often the repetition of the previous section or the entire piece or song. The turnaround may lead back to this section either harmonically, as a chord progression, or melodically.