This could be raised to part of mouth (3)
I believe the answer is:
mug
'this could' is the definition.
The definition suggests a singular noun which matches the answer.
'raised to part of mouth' is the wordplay.
'raised' shows that the letters should be reversed in order.
'to part of mouth' becomes 'gum' ('gum' is part of 'mouth').
'gum' backwards is 'MUG'.
'be' is the link.
Can you help me to learn more?
(Other definitions for mug that I've seen before include "Drinking vessel or foolish fellow" , "Face; cup; rob" , "A person easily deceived, by gum" , "Drinking vessel; dupe" , "Drinking vessel for one easily deceived" .)