The most common Korean word for “floor” is 층 (cheung). There is one more word with a similar meaning — compare them below. 「floor」는 한국어로 층.
floor; story
TOPIK 1 · noun
floor; bottom
TOPIK 2 · noun
Words and levels: TOPIK I essentials (National Institute of Korean Language standard curriculum, KOGL Type 1) · examples: Cheesepotato