'interstitial' originates from Latin, specifically the word 'interstitium,' where 'inter-' meant 'between' and 'sistere' meant 'to stand.'

'interstitium' transformed into the French word 'interstitiel,' and eventually became the modern English word 'interstitial' through Middle English.

Initially, it meant 'standing between,' but over time it evolved into its current meaning of 'relating to small spaces between things.'