casing
n. countable B2 Upper Intermediate US //ˈkeɪsɪŋ// UK //kˈeɪsɪŋ// cas·ing
n. a hard outer layer or protective cover. You use this word for the shell of a device, the border around a picture, or the edge of a building.
n. a protective outer layer, frame, or border. In computing, it refers to the capitalization of letters; in construction, it denotes the outer surface of a wall or the frame of a window.
The phone has a plastic casing.
The technician replaced the broken casing on the laptop to protect the internal components.
The architect chose a stone casing for the windows to match the historic façade of the building.