filtrée

Filtrée is the feminine singular past participle of filtrer in French. It functions as an adjective meaning “that has been filtered” and is used with feminine nouns. The masculine singular is filtré, the feminine plural filtrées, and the masculine plural filtrés; the past participle agrees in gender and number with the noun it describes. For example: eau filtrée (filtered water), solution filtrée (filtered solution).

In everyday contexts, filtrée often appears on product labels to indicate a process of clarification or purification. The term is also common in scientific and technical language to designate material or samples that have passed through filtration, such as eau filtrée, air filtré (the masculine form used with the noun air), pâte filtrée or poussière filtrée. The etymology traces back to the verb filtrer, which itself derives from Latin filtrare via Old French.

Note: In French, agreement matters; thus eau filtrée is correct because eau is feminine, whereas air filtré uses the masculine form. In English-language contexts, filtrée may be encountered in translations of labels or technical documents, but the standard English rendering is filtered.

See also: filtration, filtrate, filtrer, filter (in English) for cross-language references.