High pressure addition to cloud, maybe (6)
I believe the answer is:
upload
'cloud maybe' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'high pressure addition' is the wordplay.
'high' becomes 'up' (associated in meaning).
'pressure addition' becomes 'load' (I am not sure about this - if you are sure you should believe this answer much more).
'up'+'load'='UPLOAD'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for upload that I've seen before include "Stuff transferred" , "Transfer a file from one computer to another" , "Transfer a file from a smaller to a large computer" , "add data to system" , "Transfer (data) to a large computer" .)