- size; extent; dimensions: to determine the magnitude of an angle.
- great importance or consequence: affairs of magnitude.
- greatness of size or amount.
- moral greatness: magnitude of mind.
- Astronomy.
- the brightness of a star or other celestial body as viewed by the unaided eye and expressed by a mathematical ratio of 2.512: a star of the first magnitude is approximately 2½ times as bright as one of the second magnitude and 100 times brighter than one of the sixth magnitude. Only stars of the sixth magnitude or brighter can be seen with the unaided eye.
- absolute magnitude.
- a number characteristic of a quantity and forming a basis for comparison with similar quantities, as length.
- of utmost or major importance: an artist of the first magnitude.
- relative importance or significance
- relative size or extent
- a number assigned to a quantity, such as weight, and used as a basis of comparison for the measurement of similar quantities
- the apparent brightness of a celestial body expressed on a numerical scale on which bright stars have a low value. Values are measured by eye (visual magnitude) or more accurately by photometric or photographic methods, and range from –26.7 (the sun), through 1.5 (Sirius), down to about +30. Each integral value represents a brightness 2.512 times greater than the next highest integral value
- a measure of the size of an earthquake based on the quantity of energy released: specified on the Richter scale
