nounB1
（英）2階／（米）1階
the level of a building just above the ground level
例文
The library reading room is on the first floor.
図書館の閲覧室は2階にある。
first floor
adjectiveB1
（英）2階の／（米）1階の
located on the level just above the ground of a building
例文
They rented a small first-floor apartment near the park.
彼らは公園の近くにある小さな2階のアパートを借りた。