Places to pose on letter (5)
I believe the answer is:
sites
'places' is the definition.
(a site is a place or location)
'pose on letter' is the wordplay.
'pose' becomes 'sit' (synonyms).
'on letter' becomes 'es' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sit'+'es'='SITES'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for sites that I've seen before include "internet locations" , "Is set among building locations" , "Locates" , "Is set (anag)" , "Locations or positions, as for building" .)