'adjacency' originates from Latin, specifically the word 'adjacens,' where 'ad-' meant 'toward' and 'jacere' meant 'to lie.'

'adjacens' transformed into the French word 'adjacent,' and eventually became the modern English word 'adjacency' through Middle English.

Initially, it meant 'lying near or next to,' but over time it evolved into its current meaning of 'the state of being next to or adjoining something else.'