gwerə-, Proto-Indo-European root meaning "heavy."

It forms all or part of: aggravate; aggravation; aggrieve; bar (n.4) "unit of pressure;" bariatric; baritone; barium; barometer; blitzkrieg; brig; brigade; brigand; brigantine; brio; brut; brute; charivari; gravamen; grave (adj.); gravid; gravimeter; gravitate; gravity; grief; grieve; kriegspiel; guru; hyperbaric; isobar; quern; sitzkrieg.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit guruh "heavy, weighty, venerable;" Greek baros "weight," barys "heavy in weight," often with the notion of "strength, force;" Latin gravis, "heavy, ponderous, burdensome, loaded; pregnant;" Old English cweorn "quern;" Gothic kaurus "heavy;" Lettish gruts "heavy."

"sculpted, carved," late 14c., past-participle adjective from grave (v.) + -en (1).

"to cut in, make by incision, produce or form by incision on a hard surface," mid-15c. (implied in ingraved "engraved"), from en- (1) + obsolete verb grave "carve" (see grave (v.)) or from or modeled on French engraver. Related: Engraved; engraven; engraving.

1550s, "solemnly," from grave (adj.) + -ly (2). Meaning "in an important degree" is by 1835.

also gravedigger, 1590s, from grave (n.) + digger.

"stone over a grave," late 14c.; earlier "stone coffin" (c. 1200), from grave (n.) + stone (n.). Similar formation in German Grabstein, Dutch grafsteen, Danish gravsten.

1683, from grave (n.) + yard (n.1). Graveyard shift "late-night work" is c. 1907, from earlier nautical term, in reference to the loneliness of after-hours work.

c. 1400, "cave; mine; pit dug in the earth" (late 13c. in place names), from a Scandinavian source such as Old Norse grod "pit," or from Middle Dutch groeve "furrow, ditch" (Modern Dutch groef), both from Proto-Germanic *grobo (source also of Old Norse grof "brook, river bed," Old High German gruoba "ditch," German Grube "a pit, hole, ditch, grave," Gothic groba "pit, cave," Old English græf "ditch, grave"), from PIE root *ghrebh- (2) "to dig, bury, scratch" (see grave (n.)). Sense of "long, narrow channel or furrow," especially as cut by a tool, is 1650s. Meaning "spiral cut in a phonograph record" is from 1902. Figurative sense of "routine" is from 1842, often deprecatory at first, "a rut."

c. 1300, "dig in the ground," from hypothetical Old English *grybban, *grubbian, from West Germanic *grubbjan (source also of Middle Dutch grobben, Old High German grubilon "to dig, search," German grübeln "to meditate, ponder"), from PIE *ghrebh- (2) "to dig, bury, scratch" (see grave (n.)). Transitive sense "dig up by the roots" is from 1550s. Related: Grubbed; grubbing.

c. 1200, diggen, "to make a ditch or other excavation," a word of uncertain origin, perhaps related to dike and ditch, either via Anglo-French diguer, from Old French digue "dike" (which is ultimately from Proto-Germanic *dīk-, from PIE root *dheigw- "to stick, fix") or directly from an unrecorded Old English verb. The older native words were deolfan (see delve), grafan (see grave (v.)).

Transitive meanings "form by excavation, make by digging," also "obtain or remove by excavation" are from late 14c.; figurative sense of "discover by effort or search" is from early 15c. Meaning "to penetrate" is from mid-15c.; transitive sense of "cause to penetrate, thrust or force in" is by 1885.

In 19c. U.S. student slang it meant "study hard, give much time to study" (1827); the 20c. slang sense of "understand" is recorded by 1934 in African-American vernacular. Both probably are based on the notion of "excavate." A slightly varied sense of "appreciate" emerged by 1939. The strong past participle dug appeared in 16c. but is not etymological.