lighter n.1

"not heavy, having little actual weight," from Old English leoht (West Saxon), leht (Anglian), "not heavy, light in weight; lightly constructed; easy to do, trifling; quick, agile," also of food, sleep, etc., from Proto-Germanic *lingkhtaz (source also of Old Norse lettr, Swedish lätt, Old Frisian, Middle Dutch licht, German leicht, Gothic leihts), from PIE root *legwh- "not heavy, having little weight." The adverb is Old English leohte, from the adjective.

Meaning "frivolous" is from early 13c.; that of "unchaste" from late 14c., both from the notion of "lacking moral gravity" (compare levity). Of literature from 1590s. Light industry (1919) makes use of relatively lightweight materials. The notion in make light of (1520s) is "unimportance." Alternative spelling lite, the darling of advertisers, is first recorded 1962. Light horse "light armed cavalry" is from 1530s. Light-skirts "woman of easy virtue" is attested from 1590s. Lighter-than-air (adj.) is from 1887.

"to shed light; to set on fire," late Old English lihtan (Anglian), liehtan (West Saxon), originally transitive, "to ignite, set on fire," also in a spiritual sense, "to illuminate, fill with brightness." It is common Germanic (cognates: Old Saxon liohtian, Old High German liuhtan, German leuchten, Gothic liuhtjan "to light"), from the source of light (n.).

Meaning "furnish light for" is from c. 1200; sense of "emit light, shed light, shine" is from c. 1300. Buck writes that light is "much more common than kindle even with fire, and only light, not kindle, with candle, lamp, pipe, etc." To light up is from c. 1200 as "give light to" (a room, etc.); 1861 in reference to a pipe, cigar, etc. Related: Lighted; lighting.