room
廎 centers on a room, specifically a side room or a room within a building. The meaning is straightforward and concrete.
廎 combines 广 (building) with 頃, which likely contributes the sound. The character is rare and its exact historical development is uncertain.
The building enclosure 广 surrounds 頃, like a room tucked to the side of a house. Picture a quiet side room where time (頃) passes slowly.
For ケイ, imagine a key unlocking the door to a side room: key -> ケイ, and the room is opened.