The most common and most likely answer to this crossword clue is the 6 plus 3 letter word SENTRY BOX
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More clues leading to the result SENTRY BOX
Buddy explains!
The straight part
We know that "security area" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case security area = sentry box.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 SENTRY BOX mean?
SENTRY BOX noun- A booth erected to provide rudimentary shelter to a sentry on his post.