Theatre

Definition of theatre based on Cambridge dictionary

a building, room, or outside structure with rows of seats, each row usually higher than the one in front, from which people can watch a performance or other activity

Cambridge dictionary.

Etymology of word Theatre

The word of Theatre originates from Greek word Θέατρο (theatron – with the same meaning). The Greek word Θέατρο originates from verb Θέωμαι (theomai – to view).
The first plays were played in Ancient Greece so it is normal that many languages use the Greek word for the Theatre.