magnification. n. 1. (General Physics) the act of magnifying or the state of being magnified. 2. (General Physics) the degree to which something is magnified.3. a copy, photograph, drawing, etc, of something magnified.agnification. n. 1. (General Physics) the act of magnifying or the state of being magnified. 2. (General Physics) the degree to which something is magnified. 3. a copy, photograph, drawing, etc, of something magnified.