International head trimmed flag (4)

I believe the answer is:

iris

I'm a little stuck... Click here to teach me more about this clue!

'flag' is the definition.
(type of iris flower)

I cannot understand how the remainder of the clue works.

(Other definitions for iris that I've seen before include "Bright flower or eye part" , "Female" , "Nice flower or eye part" , "Eye diaphragm" , "plant with showy flowers" .)

I've seen this clue in The Sunday Times and The Times.

Want a hint initially instead of a full solution? Install my app

Connecting...