They house a beginner in space, possibly (7)
I believe the answer is:
palaces
'they house' is the definition.
Although both the answer and 'house' are nouns, they are not in the same form of the noun.
'a beginner in space possibly' is the wordplay.
'beginner' becomes 'L' (as in a learner driver with L-plates on their car).
'possibly' indicates anagramming the letters.
'a'+'l'+'space'='alspace'
'alspace' with letters rearranged gives 'PALACES'.
Can you help me to learn more?
(Other definitions for palaces that I've seen before include "Offical residences of sovereigns" , "kings and queens here?" , "Royal residences" .)