Marcus's lead on issue in the end raised support in press etc (5)
I believe the answer is:
media
'press etc' is the definition.
I can't judge whether this defines the answer.
'marcus's lead on issue in the end raised support' is the wordplay.
'lead' suggests taking the first letters.
'on' means one lot of letters go next to another.
'in the end' indicates one should take the final letters.
'raised' is a reversal indicator.
'support' becomes 'aid' (aiding is a kind of supporting).
The first letter of 'marcus' is 'm'.
The last letter of 'issue' is 'e'.
'aid' back-to-front is 'dia'.
'm'+'e'+'dia'='MEDIA'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for media that I've seen before include "TV networks and the like" , "News outlets" , "Mass communicators" , "means for spreading news" , "oil and water, maybe" .)