British English spelling of filter; a device for removing impurities from a liquid or gas by passing it through a porous material.
From Latin filtrare (to strain), possibly from felt-like materials used in medieval filtering, + -re (French spelling convention). This is the standard spelling in British English, while Americans use 'filter.'
British and American English split on vowels before final -r: centre/center, metre/meter, and filtre/filter. These spelling differences froze into place in the 1700s-1800s when dictionaries standardized each variety separately!
Complete word intelligence in one call. Free tier — 50 lookups/day.