magnitude

[mag-ni-tood, -tyood]

noun

1. size; extent; dimensions.

   to determine the magnitude of an angle.

2. great importance or consequence.

   affairs of magnitude.

3. greatness of size or amount.

4. moral greatness.

   magnitude of mind.

5. Astronomy.

   1. Also called apparent magnitude. Also called visual magnitude,. 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.

   2. absolute magnitude.

6. Mathematics.,  a number characteristic of a quantity and forming a basis for comparison with similar quantities, as length.

magnitude

/ ˈmæɡnɪˌtjuːd /

noun

1. relative importance or significance

   a problem of the first magnitude

2. relative size or extent

   the magnitude of the explosion

3. maths a number assigned to a quantity, such as weight, and used as a basis of comparison for the measurement of similar quantities

4. Also called: apparent magnitude. astronomy 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 See also absolute magnitude visual magnitude

5. Also called: earthquake magnitude. geology a measure of the size of an earthquake based on the quantity of energy released: specified on the Richter scale See Richter scale

magnitude

1. The degree of brightness of a star or other celestial body, measured on a logarithmic scale in which lower numbers mean greater brightness, such that a decrease of one unit represents an increase in brightness by a factor of 2.512. An object that is 5 units less than another object on the magnitude scale is 100 times more luminous. Because of refinements in measurement after the zero point was assigned, very bright objects have negative magnitudes.

2. ◆ The brightness of a celestial body as seen from Earth is called its apparent magnitude. (When unspecified, an object's magnitude is normally assumed to be its apparent magnitude.) The dimmest stars visible to the unaided eye have apparent magnitude 6, while the brightest star in the night sky, Sirius, has apparent magnitude −1.4. The full Moon and the Sun have apparent magnitudes of −12.7 and −26.8 respectively.

3. ◆ The brightness of a celestial body computed as if viewed from a distance of 10 parsecs (32.6 light-years) is called its absolute magnitude. Absolute magnitude measures the intrinsic brightness of a celestial object rather than how bright it appears on Earth, using the same logarithmic scale as for apparent magnitude. Sirius has an absolute magnitude of 1.5, considerably dimmer than Rigel which, though its apparent magnitude is 0.12, has an absolute magnitude of −8.1. Stars that appear dim in the night sky but have bright absolute magnitudes are much farther from Earth than stars that shine brightly at night but have relatively dim absolute magnitudes. The Sun, a star of only medium brightness, has an absolute magnitude of 4.8.

4. ◆ The degree of total radiation emitted by a celestial body, including all infrared and ultraviolet radiation in addition to visible light, is called its bolometric magnitude. Bolometric magnitude is generally measured by applying a standard correction to an object's absolute magnitude.

5. A measure of the total amount of energy released by an earthquake, as indicated on the Richter scale.

6. See more at Richter scale

Other Word Forms

• magnitudinous adjective
• overmagnitude noun

Word History and Origins

Origin of magnitude¹

First recorded in 1350–1400; Middle English word from Latin word magnitūdō. See magni-, -tude

Word History and Origins

Origin of magnitude¹

C14: from Latin magnitūdō size, from magnus great

Idioms and Phrases

Idioms

1. of the first magnitude, of utmost or major importance.

   an artist of the first magnitude.

Example Sentences

“I looked at the schedule in April, and a light went off in my brain that these would be historical games of great magnitude,” Hudler said.

From Los Angeles Times

A magnitude 5.6 earthquake struck Afghanistan's remote south-eastern region on Thursday night, the third quake in six days, as the death toll from the first continued to rise.

From BBC

At first, he thought it was the train at the bottom that fell, until he turned and saw the other train that was above it, and realised "the magnitude of what had taken place".

From BBC

She added it took "phenomenal courage and resilience to hold an organisation of this magnitude to account and I congratulate the officers involved".

From BBC

Many are feared trapped under the rubble of their homes after the magnitude 6.0 earthquake struck on Sunday near the country's border with Pakistan.

From BBC

Related Words

• amount 
• breadth 
• capacity 
• dimension 
• enormity 
• extent 
• immensity 
• intensity 
• measurement 
• proportion 
• quantity 
• strength 
• volume