first floor
From Longman Dictionary of Contemporary Englishfirst floorˌfirst ˈfloor noun 1 → the first floor2 → the first floorExamples from the Corpusfirst floor• Outside the shop at first floor level was a magnificent six-foot magnet.• He came up with them to Four on the first floor, Tom's room.• Father Peter, who had his private quarters on the first floor, had a compassionate understanding of the needs of women.• On the first floor there would be four equal open bays, with no connecting doors.• I climbed a narrow staircase leading to the first floor balcony.• Stairs rising to first floor with exposed timber bannister.