magnitude

American  

[mag-ni-tood, -tyood] / ˈmæg nɪˌtud, -ˌtjud /

noun

• magnitudes
  plural

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.

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idioms

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

   an artist of the first magnitude.

magnitude British  

/ 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

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magnitude Scientific  

/ măg′nĭ-to̅o̅d′ /

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

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Other Word Forms

Derived Forms

• overmagnitude
  noun
• magnitudinous
  adjective

Inflected Forms

Nouns

• magnitudes
  plural

Etymology

Origin of magnitude

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

Explanation

Earthquakes have great magnitude in that they are powerful. Their power is rated by their level of magnitude, or how much energy they release relative to other earthquakes. In math, magnitude compares numbers by powers of 10. If your weekly allowance was $10, but your brother's was $100, his allowance would be one order of magnitude higher than yours. If your sister's was $10,000, hers would be three orders of magnitude higher. A difference of that magnitude is just not fair!

Example Sentences

See Examples For:

magnitude magnitudes

Newer generations of Nvidia’s chips are orders of magnitude more energy efficient than the A100.

From The Wall Street Journal ● Aug. 18, 2026

Aid disruptions and aftershocks across the Indonesian island of Flores are fuelling fears among thousands of survivors who were displaced by a 7.7 magnitude earthquake on Saturday.

From BBC ● Aug. 17, 2026

Dozens of aftershocks have already been felt, the strongest measured at a magnitude of 6.1.

From Barron's ● Aug. 15, 2026

But he said that given the magnitude of the supply shortage, “we have to look at all options,” including working with existing suppliers to increase U.S. production.

From The Wall Street Journal ● Aug. 15, 2026

By knitting together the seams of Pangaea, Columbus set off an ecological explosion of a magnitude unseen since the Ice Ages.

From "1491" by Charles C. Mann

But the magnitudes aren’t what matters, it’s the direction.

From The Wall Street Journal ● Aug. 13, 2026

The death toll from last week's quakes - with magnitudes of 7.2 and 7.5 - has risen to 1,943 with more than 10,000 people injured and tens of thousands more unaccounted for.

From BBC ● Jun. 30, 2026

Tesla and SpaceX shares have traded in the same direction, with similar magnitudes, for the past four days.

From Barron's ● Jun. 30, 2026

The double quakes — with magnitudes of 7.2 and 7.5 — struck shortly after 6 p.m.

From Los Angeles Times ● Jun. 25, 2026

Hipparchus anticipated that stars come into being, slowly move during the course of centuries and eventually perish; it was he who first catalogued the positions and magnitudes of the stars to detect such changes.

From "Cosmos" by Carl Sagan

Related Words

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