order of magnitude

== English == === Etymology === 18th century, in the sense "magnitude (brightness class) of a star", informed by the Greek τῶν μεγάλων τάξις (tôn megálōn táxis) (Ptolemy). === Noun === order of magnitude (plural orders of magnitude) (mathematics) The class of scale or magnitude of any amount, where each class contains values of a fixed ratio (most often 10) to the class preceding it. Synonym: OOM (initialism) Hypernyms: order, scale Hyponym: ROM (“rough order of magnitude”) 2011, Enrico Fermi, Wikisource (translator), Concerning a Contradiction between the Electrodynamic and Relativistic Theory of Electromagnetic Mass, 1922, Enrico Fermi, Über einen Widerspruch zwischen der elektrodynamischen und relativistischen Theorie der elektromagnetischen Masse, Physikalische Zeitschrift, v 23, pp 340-344, However, we notice that although this contraction is of order of magnitude v 2 : c 2 {\displaystyle v^{2}:c^{2}} , it changes the most important terms of electromagnetic mass, i.e, the rest mass. ==== Translations ==== === See also === dex ballpark figure (colloquial)