The most common and most likely answer to this crossword clue is the 7 letter word GROTTOS
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More clues leading to the result GROTTOS
Buddy explains!

The straight part
We know that "caves" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case caves = grottos.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 GROTTOS mean?
GROTTOS noun- A small cave.
- An artificial cavern-like retreat.
- A Marian shrine, usually built in a cavern-like structure.
- A local organization of cavers that typically organizes trips to caves and provides information and training for caving; a caving club.
- (Satanism) A secretive name for a local group of underground Satanists.