Set from tenor penned by composer (5)
I believe the answer is:
batch
'set' is the definition.
(thesaurus)
'tenor penned by composer' is the wordplay.
'tenor' becomes 't'.
'penned by' means one lot of letters goes inside another.
'composer' becomes 'bach' (Bach is an example).
't' put into 'bach' is 'BATCH'.
'from' is the link.
(Other definitions for batch that I've seen before include "Aggregation" , "All the bread produced at one baking" , "All the loaves baked at the same time" , "Type of loaf" , "Collection of items handled together" .)