bilge n.

c. 1200, "a wallet, leather bag," from Old French bouge, boulge "wallet, pouch, leather bag," or directly from Latin bulga "leather sack," from PIE *bhelgh- "to swell," extended form of root *bhel- (2) "to blow, swell." Transferred sense of "a swelling, a rounded protuberance" is recorded by 1620s. Bilge (q.v.) might be a nautical variant. The meaning "bulging part of a military front" is from 1916, hence the World War II Battle of the Bulge (1944).

early 15c., bouget, "leather pouch, small bag or sack," from Old French bougette, diminutive of bouge "leather bag, wallet, pouch," from Latin bulga "leather bag," a word of Gaulish origin (compare Old Irish bolg "bag," Breton bolc'h "flax pod"), from PIE *bhelgh- "to swell," extended form of root *bhel- (2) "to blow, swell."

The modern financial meaning "statement of probable expenditures and revenues" (1733) is from the notion of the treasury minister keeping his fiscal plans in a wallet. Also used from late 16c. in a general sense of "a stock, store, or collection of miscellaneous items," which led to 18c. transferred sense "bundle of news," hence the use of the word as the title of some newspapers.

Proto-Indo-European root meaning "to blow, swell," "with derivatives referring to various round objects and to the notion of tumescent masculinity" [Watkins].

It forms all or part of: bale (n.) "large bundle or package of merchandise prepared for transportation;" baleen; ball (n.1) "round object, compact spherical body;" balloon; ballot; bawd; bold; bole; boll; bollocks; bollix; boulder; boulevard; bowl (n.) "round pot or cup;" bulk; bull (n.1) "bovine male animal;" bullock; bulwark; follicle; folly; fool; foosball; full (v.) "to tread or beat cloth to cleanse or thicken it;" ithyphallic; pall-mall; phallus.

It is the hypothetical source of/evidence for its existence is provided by: Greek phyllon "leaf," phallos "swollen penis;" Latin flos "flower," florere "to blossom, flourish," folium "leaf;" Old Prussian balsinis "cushion;" Old Norse belgr "bag, bellows;" Old English bolla "pot, cup, bowl;" Old Irish bolgaim "I swell," blath "blossom, flower," bolach "pimple," bolg "bag;" Breton bolc'h "flax pod;" Serbian buljiti "to stare, be bug-eyed;" Serbo-Croatian blazina "pillow."

An extended form of the root, *bhelgh- "to swell," forms all or part of: bellows; belly; bilge; billow; bolster; budget; bulge; Excalibur; Firbolgs.

An extended form of the root, *bhleu- "to swell, well up, overflow," forms all or part of: affluent; bloat; confluence; effluent; effluvium; efflux; fluctuate; fluent; fluid; flume; fluor; fluorescence; fluoride; fluoro-; flush (v.1) "spurt, rush out suddenly, flow with force;" fluvial; flux; influence; influenza; influx; mellifluous; phloem; reflux; superfluous.