Fragment of molar on back of mouth (4)
I believe the answer is:
oral
'mouth' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?
'fragment of molar on back' is the wordplay.
'fragment of' says the answer is hidden in the clue (I've seen this in other clues).
'back' says the letters should be written backwards.
'laro' is hidden within 'molar on'.
'laro' written backwards gives 'ORAL'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for oral that I've seen before include "By word of mouth, like some exams" , "Related to the mouth" , "Spoken test" , "Viva voce" , "Kind of exam" .)