The most common and most likely answer to this crossword clue is the 8 letter word FANLIGHT
I've seen this crossword clue in Independent
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More clues leading to the result FANLIGHT
- Steps round an elevated aperture
- Stairs concealing an opening over a door
- Some steps outside an upper window
- Lover given easy opening
- Xmas illumination not well-ventilated? A knight should open that window
- Fellow left in darkness grabs a window
- Window nut, easily moved
- Staircase containing a new window
- Escape taking in an elevated window
- An in-flight means of providing illumination
Buddy explains!

The straight part
We know that "window" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case window = fanlight.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 FANLIGHT mean?
FANLIGHT noun- A semicircular or semioval window over a door or other window, normally having a fan-like structure of ribs; sometimes hinged to the transom