Pronunciation

change

Singular
filter

Plural
filters

 
An air filter
  1. (countable) A filter is a piece of equipment that put gas or liquid through to take out the parts you don't want, to clean it.
    Car engines have a fuel filter to keep the fuel clean.

Plain form
filter

Third-person singular
filters

Past tense
filtered

Past participle
filtered

Present participle
filtering

  1. (transitive) If you filter a gas or a liquid, you put it through something that takes out the parts you don't want.
    We filter the water.