'perpendicular' originates from Latin, specifically the word 'perpendicularis,' where 'per-' meant 'through' and 'pendere' meant 'to hang.'

'perpendicularis' transformed into the Old French word 'perpendiculer,' and eventually became the modern English word 'perpendicular' through Middle English.

Initially, it meant 'hanging through or straight,' but over time it evolved into its current meaning of 'at a right angle.'