The most common and most likely answer to this crossword clue is the 7 letter word DEPOSIT
I've seen this crossword clue in The Guardian
D
E
P
O
S
I
T
More clues leading to the result DEPOSIT
- Carefully place silicon in store
- Security is regressive in storehouse
- Security is nothing to write about, entering department
- Please take a chair, to accept record down-payment
- Start to type one's newspaper article up, to put by for later
- Top side playing for initial sum of money
- Bound to involve bribe when turning over bank …
- Security is raised in warehouse
- Settlement is rejected in warehouse
- Place that attracts interest
Buddy explains!

The straight part
We know that "Security" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case security = deposit.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 DEPOSIT mean?
DEPOSIT noun- Sediment or rock that is not native to its present location or is different from the surrounding material. Sometimes refers to ore or gems.
- That which is placed anywhere, or in anyone's hands, for safekeeping; something entrusted to the care of another.
- Money placed in an account.
- Anything left behind on a surface.
- A sum of money or other asset given as an initial payment, to show good faith, or to reserve something for purchase.
- A sum of money given as a security for a borrowed item, which will be given back when the item is returned, e.g. a bottle deposit or can deposit
- A place of deposit; a depository.
- To lay down; to place; to put.
- To lay up or away for safekeeping; to put up; to store.
- To entrust one's assets to the care of another. Sometimes done as collateral.
- To put money or funds into an account.
- To lay aside; to rid oneself of.