Docks each for taking part in games (8)

I believe the answer is:

seaports

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

'docks' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.

'each for taking part in games' is the wordplay.
'each for' becomes 'ea' (I can't justify this - if you can you should give a lot more credence to this answer).
'taking part in' indicates putting letters inside.
'games' becomes 'sports' (I've seen this before).
'ea' put into 'sports' is 'SEAPORTS'.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.