All 3 Uses

atrium
in
The Hate U Give
(Edited)

I go inside and scan the atrium for Maya, Hailey, or Chris.
p. 74.5 *

atrium = large public room
Well, whispering really, in little huddles in the halls and the atrium like they're discussing plays during a basketball game.
p. 180.2
The atrium's busy as usual with people talking to their little cliques or playing around.
p. 334.1

Definitions:

(1) (atrium as in: atrium of the building)
a central open space in a building -- often a large skylit hall near the entrance

In ancient Roman houses and early Christian churches, an atrium was an open courtyard. In many modern buildings, it is an indoor space that may include plants, water features, and balconies or walkways to other rooms.
(2) (atrium as in: right atrium of the heart)
chamber from which blood enters the heart
(3) (meaning too rare to warrant focus)
Much less commonly, atrium can refer to anatomical structures other than the heart.