filter
UK: ˈfɪltə | US: ˈfɪltər
n. a porous device for removing impurities from liquids or gases
vt. to pass a substance through a device to separate particles
vi. to move gradually or selectively (e.g., "Sunlight filtered through the leaves.")
The word "filter" traces back to Medieval Latin filtrum, meaning "felt" (a porous material used for straining liquids). The Old French filtre adopted this term, referring to the device itself. The morpheme fil preserves the original notion of a permeable barrier, while -ter functions as an instrumental suffix, highlighting its purpose as a tool. The evolution reflects a shift from the material (felt) to its functional application (straining device).
The coffee filter ensures a smooth brew.
She filtered the water to remove sediment.
News slowly filtered out to the public.
The air filter needs replacement.
He filtered his thoughts before speaking.