The most common and most likely answer to this crossword clue is the 10 letter word COLLECTORS
I've seen this crossword clue in Independent
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Buddy explains!
The straight part
We know that "They gather" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they gather = collectors.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 COLLECTORS mean?
COLLECTORS noun- A person who or thing that collects, or which creates or manages a collection.
- A person who is employed to collect payments.
- The amplified terminal on a bipolar junction transistor.
- A compiler of books; one who collects scattered passages and puts them together in one book.
- One holding a Bachelor of Arts in Oxford, formerly appointed to superintend some scholastic proceedings in Lent.
- A major sewer which collects sewerage from a number of smaller branch sewers
- A mafioso whose task is to collect protection money from small businesses