Temporary accommodation at American college grounds (6)
I believe the answer is:
campus
'college grounds' is the definition.
(university or college site)
'temporary accommodation at american' is the wordplay.
'temporary accommodation' becomes 'camp' (people stay in a camp temporarily).
'at' means one lot of letters go next to another.
'american' becomes 'us' (abbreviation for United States).
'camp'+'us'='CAMPUS'
(Other definitions for campus that I've seen before include "Grounds of university or college" , "University grounds, etc" , "Higher education sector" , "educational grounds" , "College estate" .)