Final answer:
'Crescendo poco rall' is a musical notation that means to gradually increase the volume and then slow down the tempo of the music.
Step-by-step explanation:
Crescendo poco rall is a musical notation that instructs the performer to gradually increase the volume of the music and then gradually slow down the tempo. 'Crescendo' means to get louder, while 'poco rall' is short for 'poco rallentando' which means to slow down a little. This notation is commonly used by composers to add dynamic and expressive elements to the music.