A copy sent (3)
I believe the answer is:
fax
'a copy' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for fax that I've seen before include "Electronic transmission" , "Means of communication" , "Transmission of exact copies of documents electronically" , "Modern method of transmitting printed matter by phone" , "Transmit document" .)