be under the impression that ... Definition

impression
noun

1. An idea or effect, especially a favourable one, produced in the mind or made on the senses.

Example: It is vital to create a good impression
2. A vague or uncertain idea, notion or belief.

Example: I got the impression he was lying
Thesaurus: awareness, opinion, recollection, belief, sense, conviction, suspicion, idea, hunch.
3. An act or the process of impressing (see impress¹).
4. A mark or stamp produced by, or as if by, impressing or pressure.

Thesaurus: dent, indentation, imprint, mark, stamp.
5. An imitation, especially a caricature, of a person, or an imitation of a sound, done for entertainment.

Example: He does impressions of pop stars
Thesaurus: imitation, impersonation, parody, burlesque, take-off (slang).
6. The number of copies of a book, newspaper, etc printed at one time.
7a. printing.
The pressing of a prepared inked plate or type on to the paper, etc being printed;
7b. printing.
A copy made in this way.

Idiom: be under the impression that ...

To think, feel or believe (especially wrongly) that ....
Example: I was under the impression that you were paying for this meal

Etymology: 14c.