In DJing, phrasing, also called stage matching, refers to alignment of phrase

Phrase (music)

In music and music theory, phrase and phrasing are concepts and practices related to grouping consecutive melodic notes, both in their composition and performance...

s of two tracks in a mix. This allows the transition between the tracks to be done without breaking the musical structure.

Phrasing is an aspect of beatmixing

Beatmixing

Beatmixing is a disk jockey technique of playing two songs at the same time so that the beats of one song occur at the same time as the other.-History:...

, not a separate technique. Because most electronic dance music

Electronic dance music

Electronic dance music is electronic music produced primarily for the purposes of use within a nightclub setting, or in an environment that is centered upon dance-based entertainment...

 tracks have 4/4 time signature

Time signature

The time signature is a notational convention used in Western musical notation to specify how many beats are in each measure and which note value constitutes one beat....

and a simple structure of 16-bar phrases, to align the phrases of two tracks it is often enough to start the track to be mixed in at a phrase boundary in the track currently playing. Careful phrasing can produce a seamless mix by making the breaks in two tracks coincide, or aligning the break in one track with the start of the beat in the other.