Elevenses, though it’s not quite eleven (3)
I believe the answer is:
tea
'elevenses' is the definition.
(I've seen this before)
'it's not quite eleven' is the wordplay.
'not quite' means to remove the last letter.
'eleven' becomes 'ea' (I am not sure about this - if you are sure you should believe this answer much more).
'ts' with its final letter taken off is 't'.
't'+'ea'='TEA'
'though' acts as a link.
Can you help me to learn more?
(Other definitions for tea that I've seen before include "Char" , "Assam or Darjeeling, for example" , "Darjeeling, e.g." , "Light afternoon repast" , "grass" .)