Definition of en masse adverb from the Oxford Advanced Learner's Dictionary

 

en masse

 adverb
adverb
BrE BrE//ˌɒ̃ ˈmæs//
 
; NAmE NAmE//ˌɑ̃ː ˈmæs//
 
(from French)
 
jump to other results
all together, and usually in large numbers The young folk were emigrating en masse. Word Origin late 18th cent.: French, ‘in a mass’.
See the Oxford Advanced American Dictionary entry: en masse