con ‧ gre ‧ gate /ˈkɒŋɡrəɡeɪt, ˈkɒŋɡrɪɡeɪt $ ˈkɑːŋ-/ BrE AmE verb [intransitive]
[ Date: 1400-1500 ; Language: Latin ; Origin: past participle of congregare , from com- ( ⇨ COM- ) + grex 'crowd' ]
to come together in a group OPP disperse :
Crowds began to congregate to hear the President’s speech.