High space that ticks boxes (5)
I believe the answer is:
attic
'high' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
I also know that 'high' relates to this answer.
'space that ticks boxes' is the wordplay.
'boxes' indicates the answer is hidden within the clue (to box can mean to contain).
'ATTIC' is hidden within 'space that ticks'.
Can you help me to learn more?
(Other definitions for attic that I've seen before include "The highest room" , "Tacit (anag.)" , "Greek - garret" , "Ancient Greek dialect - top room" , "Area at the top of the house" .)