bratwurst n.

German sausage, 1855, from German Wurst, from Old High German wurst "sausage," probably etymologically "mixture," from Proto-Germanic *wursti-, from PIE *wers- (1) "to confuse, mix up" (see war (n.)).

late 13c., "boar's flesh;" early 14c., "flesh of a muscular part of the body," from Old French braon "fleshy or muscular part, buttock," from Frankish *brado "ham, roast" or some other Germanic source, from Proto-Germanic *bred-on- (source also of Old High German brato "tender meat," German Braten "roast," Old Norse brað "raw meat," Old English bræd "flesh"), from PIE *bhre- "burn, heat," from root *bhreu- "to boil, bubble, effervesce, burn."

The etymological sense is "piece of meat suitable for roasting." "The specific sense 'boar's flesh' is exclusively of English development, and characteristic of English habits" [OED]. The meaning "well-developed muscles, muscular strength" is from 1865.

also *bhreuə-, *bhreəu-, Proto-Indo-European root meaning "to boil, bubble, effervesce, burn," with derivatives referring to cooking and brewing.

It forms all or part of: barm; barmy; bourn (n.1) "small stream;" braise; bratwurst; brawn; brawny; braze (v.1) "to expose to the action of fire;" brazier; Brazil; bread; breed; brew; broth; broil (v.2) "to quarrel, brawl;" brood; effervesce; effervescence; effervescent; embroil; ferment; fervent; fervid; fervor; imbroglio.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit bhurnih "violent, passionate;" Greek phrear "well, spring, cistern;" Latin fervere "to boil, foam," Thracian Greek brytos "fermented liquor made from barley;" Russian bruja "current;" Old Irish bruth "heat;" Old English breowan "to brew," beorma "yeast;" Old High German brato "roast meat."