Case of tiny Post Office error in print (4)
I believe the answer is:
typo
'error in print' is the definition.
'typo' can be an answer for 'error' (typographical error). I'm not certain of the 'in print' bit.
'case of tiny post office' is the wordplay.
'case of' says to hollow out the word (remove centre letters) (like emptying a case).
'post office' becomes 'po' (abbreviation).
'tiny' with its centre removed is 'ty'.
'ty'+'po'='TYPO'
Can you help me to learn more?
(Other definitions for typo that I've seen before include "What's not right" , "literal, perhaps" , "Character flaw" , "Literal error in printed matter, in short" , "Mistake in printed matter, in short" .)