say it: MAG-nuh-tood
magnitude is a noun meaning "the property of relative size or extent (whether large or small)". It carries 3 recorded senses.
the property of relative size or extent (whether large or small)
“they tried to predict the magnitude of the explosion”
“about the magnitude of a small pea”
a number assigned to the ratio of two quantities; two quantities are of the same order of magnitude if one is less than 10 times as large as the other; the number of magnitudes that the quantities differ is specified to within a power of 10
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for magnitude come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.