What does the word impression mean?

Usage examples for impression

  1. We were under the impression...." – Major Vigoureux by A. T. Quiller-Couch
  2. What is the meaning of " feeling," " impression," here? – The Psychology of Beauty by Ethel D. Puffer
  3. That's the only thing I had in mind when I spoke, and if I gave you any other impression I'm sorry I said what I did. – The Lost Valley by J. M. Walsh