They are joined by those seeking an explanation (4)
I believe the answer is:
dots
'they' is the definition.
Both the answer and definition are plural nouns.
Maybe you can see an association between them that I don't see?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for dots that I've seen before include "Tiny spots" , "Tiny circles" , "Shorter signals in the Morse code" , "Short signals in Morse cods" , "Very small round shapes" .)