Fashionable small cross raised within building (7)
I believe the answer is:
indoors
'fashionable small cross raised within building' is the definition.
I can't judge whether this defines the answer.
'fashionable small cross raised' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'small' becomes 's' (abbreviation - e.g. clothes size).
'cross' becomes 'rood' (term for a crucifix).
'raised' says the letters should be written backwards (going up in a down clue).
's'+'rood'='srood'
'srood' back-to-front is 'doors'.
'in'+'doors'='INDOORS'
Can you help me to learn more?
(Other definitions for indoors that I've seen before include "Having returned to pavilion" , "Within house" , "home" , "Within the four walls" , "Within a building" .)