Slow, in music (7)
'slow in music' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lento that I've seen before include "Slow musically" , "It's slower than adagio" , "How one scores slowly" , "Old sayings" , "Slowly (mus.)" .)
(Other definitions for andante that I've seen before include "Unhurried pace" , "Fairly slow movement" , "(Of tempo) moderately slow" , "progressing slowly" , "Musical instruction" .)