filter-n; 3 Senses

Sense Number 1: a porous device that removes impurities from a substance

Commentary: FILTER[+artifact][+device][+porous][+remover][+of_impurities][+in_substance]

This brand of cigarette uses an active charcoal filter.
Mary put a filter on her sink faucet to remove trace elements from the tap water.
The winemaker used no filters during the fermentation process.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: an electrical device that alters the frequency spectrum of a signal

Commentary: FILTER[+artifact][+device][+electrical][+alteration][+of_frequency_spectrum][+of_signal]

The engineer ran the signal through a low-pass filter.
This headset has a noise-reduction filter.

WordNet 3.0 Sense Numbers: 2

Sense Number 3: a plate or screen that selectively absorbs wavelengths of light

Commentary: FILTER[+artifact][+device][+plate][+absorber][+selective][+of_light]

The photographer used a blue filter and a fast exposure for this picture.
John put a special filter over the lens of his telescope in order to look at the sun.
The clouds act as a filter and block certain wavelengths of sunlight.

WordNet 0.0 Sense Numbers: 1b