Insect or defect in a computer program (3)
I believe the answer is:
bug
I believe this is a double definition.
'insect' is the first definition.
(I know that insect can be written as bug)
'defect in a computer program' is the second definition.
(I've seen this before)
(Other definitions for bug that I've seen before include "Annoy; insect" , "Small crawling creature, now in computer programs" , "stripped down motor" , "Insect, or flaw in computer program" , "Hidden microphone" .)