Numbers of US locums worked without iodine (4,5)
I believe the answer is:
soul music
'numbers of us locums worked without iodine' is the definition.
I can't judge whether this defines the answer.
'us locums worked without iodine' is the wordplay.
'worked' indicates anagramming the letters.
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'iodine' becomes 'I' (chemical symbol).
'us'+'locums'='uslocums'
'uslocums' anagrammed gives 'soulmusc'.
'soulmusc' enclosing 'i' is 'SOUL MUSIC'.
Can you help me to learn more?
(Other definitions for soul music that I've seen before include "work of Franklin" , "Late 1950s' genre combining R & B and gospel" , "Songs from Aretha Franklin, for example" , "Blend of blues, jazz etc." , "urban sound" .)