foyer (n.)

"lobby of a theater or opera house," 1859, from French foyer "green room, room for actors when not on stage," literally "fireplace," from Old French foier "furnace, stove, hearth, fireplace" (12c.), from Latin focarium, noun use of neuter of adjective focarius "having to do with the hearth," from focus "hearth, fireplace" (see focus (n.)).