filter Etymology

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filter (n.)

early 15c., from O.Fr. filtre and directly from M.L. filtrum "felt," which was used to strain impurities from liquid, from W.Gmc. *filtiz(see felt). Of cigarettes, from 1908.

filter (v.)

1570s, from M.L. filtrare, from filtrum (see filter (n.)). The figurative sense is from 1830. Related: Filtered; filtering.