the.com/glasshouse

means A building with walls and roof largely made of glass, used especially for growing plants — or, in British slang, military slang for a prison.

from Straightforwardly literal: 'glass' plus 'house,' describing a structure built from panes of glass, first used for greenhouses from around the 17th-18th century as glassmaking became affordable enough to build with. The proverb 'people who live in glasshouses shouldn't throw stones' (warning against criticizing others when you're equally vulnerable) is recorded from the 17th century and cemented the phrase in idiom. The British military slang sense — 'glasshouse' meaning a prison or guardroom — comes from an actual glass-roofed military prison in Aldershot, England, built in the 1800s; the nickname stuck and spread to military lockups generally.