Filtering

How to spell filtering

9 letters · 3 syllables

How to pronounce filtering

Say the part in capitals loudest.

What does filtering mean?

1. verbPassing a substance or stream of information through something that removes unwanted parts.

Filtering in a sentence

• The new water filtering system removes most of the chlorine taste.

• Filtering the spam from her inbox saved her almost an hour each morning.

Where does filtering come from?

Language of origin: Latin

The word goes back to the Medieval Latin filtrum, which literally meant a piece of felt, the matted wool cloth that was packed into a funnel to strain liquids and trap impurities. French turned this into filtre, and the strainer itself lent its name to the action of passing something through it. English adopted 'filter' as both a noun and a verb in the 1500s and 1600s, and the present participle 'filtering' developed naturally with the regular -ing ending. It is a neat reminder that a kitchen or laboratory filter was once quite literally a wad of felt, and the two words still share that ancient root. The spelling stays straightforward because the base 'filter' simply keeps its 'er' before the suffix, with no doubling of the final letter.

How the word is built

• filter (strainer, from Latin filtrum: felt used to strain)
• -ing (verb/gerund suffix)