It forms all or part of: acromegaly; Almagest; Charlemagne; maestro; magisterial; magistral; magistrate; Magna Carta; magnate; magnitude; magnum; magnanimity; magnanimous; magni-; Magnificat; magnificence; magnificent; magnify; magniloquence; magniloquent; Magnus; maharajah; maharishi; mahatma; Mahayana; Maia; majesty; major; major-domo; majority; majuscule; master; maxim; maximum; may (v.2) "to take part in May Day festivities;" May; mayor; mega-; megalo-; mickle; Mister; mistral; mistress; much; omega.
It is the hypothetical source of/evidence for its existence is provided by: Armenian mets "great;" Sanskrit mahat- "great, mazah- "greatness;" Avestan mazant- "great;" Hittite mekkish "great, large;" Greek megas "great, large;" Latin magnus "great, large, much, abundant," major "greater," maximus "greatest;" Middle Irish mag, maignech "great, large;" Middle Welsh meith "long, great."
island in the Balearics, from Latin maior "larger," irregular comparative of magnus "large, great" (from PIE root *meg- "great"); so called because it is the largest of the three islands. Related: Majorcan.
Scandinavian masc. proper name, popular with early kings, the first to use it was Magnus I, king of Norway and Denmark (d. 1047), who evidently took it in emulation of Charlemagne (Latin Carolus Magnus) under the impression that magnus (Latin, literally "great," from PIE root *meg- "great") was a personal name.
before vowels meg-, word-forming element often meaning "large, great," but in physics a precise measurement to denote the unit taken a million times (megaton, megawatt, etc.), from Greek megas "great, large, vast, big, high, tall; mighty, important" (fem. megale), from PIE root *meg- "great." Mega began to be used alone as an adjective by 1982.
High-speed computer stores 2.5 megabits [headline in "Electronics" magazine, Oct. 1, 1957]