magnitude Definition

magnitude
noun

1. Importance or extent.

Thesaurus: importance, consequence, significance, moment, degree, greatness, eminence, grandeur.
2. Physical size; largeness.

Thesaurus: dimension, extent, size, breadth, measure, amplitude, bulk, capacity, expanse, mass, volume, weight, proportion.
3. astron.
The degree of brightness of a star.

Idiom: of the first magnitude

Said of a star: of the first degree of brightness.

Of a very important, significant or catastrophic kind.
Example: a disaster of the first magnitude

Etymology: 14c: from Latin magnitudo, from magnus great.