### Clue: I, for one, pressed into backing art galleries … (8)
### Answer: TRIFORIA 
 ### Explanation: a triforium is a gallery above the arches of an aisle in a church – a word I've seen before thanks to looking up 'clerestory' in another crossword…
 **I** plus **FOR** plus **I**="one"; all inside a reversal/"backing" of **ART