The most common and most likely answer to this crossword clue is the 5 letter word ATTIC
I've seen this crossword clue in The Daily Telegraph
A
T
T
I
C
More clues leading to the result ATTIC
- Greek for ‘Room at the Top’?
- Old Greek version of 'Room at the Top'?
- Classically elegant trellis with sides lopped
- A plan to get rid of electric current in upper floor
- Old Greek goat tickling nurses
- One about to shelter under a dry space in building
- High level of trainee fliers taking it up
- Some latticework in room
- Greek screen with ends cut off
- Room’s window having no frame
Buddy explains!

The straight part
We know that "room" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case room = attic.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ATTIC mean?
ATTIC noun- The space, often unfinished and with sloped walls, directly below the roof in the uppermost part of a house or other building, generally used for storage or habitation.