Half of Sicily is like this (3)
I believe the answer is:
sic
'like this' is the definition.
The definition suggests a singular noun but the answer is not.
'half of sicily' is the wordplay.
'half of' suggests halving the letters.
'sicily' with half the letters taken is 'SIC'.
'is' is the link.
Can you help me to learn more?
(Other definitions for sic that I've seen before include "Written exactly thus" , "Thus among musicians" , "As it stands, in printing" , "Thus in Corsica" , "'Thus, in printing (3)'" .)