Shoots back into a little bar (5)
I believe the answer is:
serif
'a little bar' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'shoots back' is the wordplay.
'shoots' becomes 'fires' (firing is a kind of shooting).
'back' says the letters should be written in reverse.
'fires' in reverse letter order is 'SERIF'.
'into' acts as a link.
Can you help me to learn more?
(Other definitions for serif that I've seen before include "Projection at a letter's end" , "additional line in letter?" , "Short line at the end of the main stroke of a letter" , "Small line used in printing type" , "Feature of some typefaces" .)