Crossword Genius

Courts large family all at once (5)

Ross

I believe the answer is:

quads

I'm a little stuck... Click here to teach me more about this clue!

'courts' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Maybe there's an association between them I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for quads that I've seen is " Double 17".)

I've seen this clue in The Guardian.
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