Host; military (4)
I believe the answer is:
army
I believe this is a double definition.
'host' is the first definition.
(both can mean a large number of people)
'military' is the second definition.
(the armed forces)
(Other definitions for army that I've seen before include "Large military body" , "Fighting force" , "Military land force" , "See 6" , "See 17" .)