It's in fashion, a lot, for linking computers (5)
I believe the answer is:
modem
'linking computers' is the definition.
I can't judge whether this defines the answer.
'it's in fashion a lot' is the wordplay.
I cannot quite see how this works, but
'fashion' could be 'mode' (synonyms) and 'mode' is found within the answer.
'lot' could be 'm' and 'm' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for modem that I've seen before include "Communications device" , "Computer interface" , "Device for connecting two computers" , "Device for connecting computers via a phone line" , "Device linking computers via a telephone line" .)