Accelerando (Italian: becoming faster) is a term in general use to show that the music should be played at an increasing speed.

musical instruction indicating a passage to be played with increasing speed, 1842, from Italian accelerare, from Latin accelerare "to hasten, quicken" (see accelerate).

 Accelerate or gradually increase the tempo or speed of the music.

(n) a gradually increasing tempo of music(adj) gradually increasing in tempo(adv) with increasing speed

(accel.) gradually getting faster An increase in the speed of the music.

gradually getting quicker

Getting gradually faster.

 – accelerating; gradually increasing the tempo

gradually becoming faster

a musical term indicating that the tempo should be gradually increased. The opposite of ritardando.

 Getting faster.

To gradually quicken the tempo of the song

A gradual increase in tempo, resulting in getting faster.

[It] (accel.) accelerate, gradually get faster.

Getting faster

becoming faster (usually abbreviated: accel.). See also: “stringendo”.

A symbol used in musical notation indicating to gradually quicken tempo.

An indication in Music notation to gradually increase the tempo. Often abbreviated to “accel”

Gradually accelerating or getting faster. Abbreviated by accel. or accelº.   More about tempo-terminology. Example Franz Liszt: Hungarian Rhapsody, No. 2 

Italian tempo marking meaning to gradually accelerate or speed up.