War distributed by marines a lot (5)

I believe the answer is:
swarm
This could be a double definition.
'war distributed by marines' is the first definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'a lot' is the second definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for swarm that I've seen before include "Move in large numbers like locusts" , "Crowd of e.g. bees" , "Flight of bees" , "Host" , "Large cloud (of insects)" .)
