noun

1. the act of impressing
2. a result or effect of impressing; specif.,
   1. a mark, imprint, etc. made by physical pressure
   2. an effect produced, as on the mind or senses, by some force or influence
   3. the effect produced by any effort or activity hard cleaning made little impression on the stain
3. a notion, feeling, or recollection, esp. a vague one
4. a first or single coat of paint or color
5. an imitation or mimicking intended as a caricature or amusing impersonation
6. Dentistry
   1. the imprint of the teeth and surrounding tissues in wax, plaster, etc., used as a mold in making dentures
   2. the mold used to make an inlay
7. Printing
   1. the pressing or pressure of type or plates as on paper; printing
   2. a printed copy
   3. all the copies printed in a single operation from a set of unaltered type or plates

Etymology: ME impressioun < OFr impression < L impressio