Page got certain segment upset (5)
I believe the answer is:
recto
'page' is the definition.
(right-hand page of an open book)
'got certain segment upset' is the wordplay.
'RECTO' is hidden back-to-front within the letters.
But, I am unsure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for recto that I've seen before include "front of leaf" , "Odd-numbered page" , "Side of paper" , "Right-hand pages of book" , "The right-hand page or leaf of a book" .)