What is the meaning of filter?

noun

• Device that removes something from whatever passes through it.
• An electrical device that alters the frequency spectrum of signals passing through it.

verb

• Remove by passing through a filter.
  • usage: "filter out the impurities"
  • synonyms: filtrate, strain, separate out, filter out
• Pass through.
  • usage: "Water permeates sand easily"
  • synonyms: percolate, sink in, permeate
• Run or flow slowly, as in drops or in an unsteady stream.
  • usage: "water trickled onto the lawn from the broken hose"; "reports began to dribble in"
  • synonyms: trickle, dribble