Cut bottom off Hibernian flag
I believe the answer is:
iris
'flag' is the definition.
(type of iris flower)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for iris that I've seen before include "may open up in camera" , "Goddess of the rainbow in the eye" , "Eye diaphragm" , "Flower - rainbow" , "Camera diaphragm" .)