Tune from mass organised yodel (6)
I believe the answer is:
melody
'tune' is the definition.
(I know that tune can be written as melody)
'mass organised yodel' is the wordplay.
'mass' becomes 'm' (symbol used in Physics e.g. f=ma).
'organised' indicates an anagram.
'yodel' anagrammed gives 'elody'.
'm'+'elody'='MELODY'
'from' acts as a link.
(Other definitions for melody that I've seen before include "Harmonious tune or song" , "Agreeable succession of musical sounds" , "A pleasant tune or song" , "Musical line" , "Sweet music, tuneful song" .)