See moment to send souvenirs (9)
I believe the answer is:
mementoes
'souvenirs' is the definition.
(I know this)
'see moment to send' is the wordplay.
'to send' indicates anagramming the letters (I've seen 'sent' mean this (send can mean to excite or stimulate)).
'see'+'moment'='seemoment'
'seemoment' anagrammed gives 'MEMENTOES'.
(Other definitions for mementoes that I've seen before include "Souvenirs of past events" , "memorabilia" .)