Big
Middle English (in the sense ‘strong, mighty’): of unknown origin.
wiktionary
From a northern Middle English dialectal term big, bigge(“powerful, strong”) possibly from a dialect of Old Norse. Ultimately perhaps a derivative of Proto-Germanic *bugja-(“swollen up, thick”), from Proto-Indo-European *bʰew-, *bu-(“to swell”), [1] in which case big would be related to bogey, bugbear, and bug.
Compare dialectal Norwegian bugge(“great man”), Low German Bögge, Boggelmann.
From Middle English biggen, byggen, from Old Norse byggja, byggva(“to build, dwell in, inhabit”), a secondary form of Old Norse búa(“to dwell”), related to Old English būan(“to dwell”). Cognate with Danish bygge, Swedish bygga.
From Middle English byge, from Old Norse bygg(“barley, probably Hordeum vulgare, common barley”), from Proto-Germanic *bewwuz(“crop, barley”). Cognate with Old English bēow(“barley”).
etymonline
big (adj.)
c. 1300, at first found chiefly in northern England and north Midlands writing, "powerful, strong," of obscure origin, possibly from a Scandinavian source (compare Norwegian dialectal bugge "great man"). Old English used micel (see much) in many of the same senses. It came into general use c. 1400. Meaning "of great size" is late 14c.; that of "full-grown, grown up" is attested from late 14c. Sense of "important, influential, powerful" is from c. 1400. Meaning "haughty, inflated with pride" is from 1570s. Meaning "generous" is U.S. colloquial by 1913.
Big band as a musical style is from 1926. Slang big head "conceit" is first recorded 1850. Big business "large commercial firms collectively" is from 1913 (before that it meant "a profitable income in business"). Big top "main tent of a circus" is from 1895. Big game "large animals hunted for sport" is from 1864. Big house "penitentiary" is U.S. underworld slang first attested 1915 (in London, "a workhouse," 1851). In financial journalism, big ticket items so called from 1956. Big lie is from Hitler's grosse Lüge.
