Middle English bladdre, from Old English blædre (West Saxon), bledre (Anglian) "urinary bladder," also "blister, pimple," from Proto-Germanic *blodram "something inflated" (source also of Old Norse blaðra, Old Saxon bladara, Old High German blattara, German Blatter, Dutch blaar), from PIE root *bhle- "to blow." The extended senses date from early 13c., from animal bladders being used for buoyancy, storage, etc.
"to rise from or out of anything that surrounds, covers, or conceals; come forth; appear, as from concealment," 1560s, from French émerger and directly from Latin emergere "bring forth, bring to light," intransitively "arise out or up, come forth, come up, come out, rise," from assimilated form of ex "out" (see ex-) + mergere "to dip, sink" (see merge). The notion is of rising from a liquid by virtue of buoyancy. Related: Emerged; emerging.
late 14c., "inordinate self-esteem, arrogance," especially "self-satisfaction over one's accomplishments or qualities, vainglory" (early 15c.), from Old French elacion "elation, conceit, arrogance, vanity," from Latin elationem (nominative elatio) "a carrying out, a lifting up," noun of action from elatus "elevated," form used as past participle of efferre "carry out, bring out, bring forth, take away," from assimilated form of ex "out" (see ex-) + lātus "carried, borne" (see oblate (n.)), past participle of the irregular verb ferre "carry" (from PIE root *bher- (1) "to carry," also "to bear children"). Metaphoric sense of "a lifting of spirits" was in Latin and has always been the principal meaning in English. More positive sense of "buoyancy, joyfulness" is from 1750 in English.
"that roars or bellows; making or characterized by noise or disturbance," late 14c., present-participle adjective from roar (v.). Used of periods of years characterized by noisy revelry, especially roaring twenties (1930, which OED credits to "postwar buoyancy"); but also, in Australia, roaring fifties (1892, in reference to the New South Wales gold rush of 1851). Roaring Forties in reference to exceptionally rough seas between latitudes 40 and 50 south, is attested from 1841.
The "roaring fifties" are still remembered as the days when Australia held a prosperity never equalled in the world's history and a touch of romance as well. The gold fever never passed away from the land. [E.C. Buley, "Australian Life in Town and Country," 1905]
Roaring boys, roaring lads, swaggerers : ruffians : slang names applied, about the beginning of the seventeenth century, to the noisy, riotous roisterers who infested the taverns and the streets of London, and, in general, acted the part of the Mohocks of a century later. Roaring girls are also alluded to by the old dramatists, though much less frequently. [Century Dictionary]
This is from the use of roar (v.) in old London slang for "behave in a riotous and bullying manner" (1580s).
apparently an early Middle English merger of three related Old English nouns, flota "boat, fleet," flote "troop, flock," flot "body of water, sea;" all from the source of float (v.). The early senses were the now-mostly-obsolete ones of the Old English words: "state of floating" (early 12c.), "swimming" (mid-13c.); "a fleet of ships; a company or troop" (c. 1300); "a stream, river" (early 14c.). From c. 1300 as an attachment for buoyancy on a fishing line or net; early 14c. as "raft." Meaning "platform on wheels used for displays in parades, etc." is from 1888, probably from earlier sense of "flat-bottomed boat" (1550s). As a type of fountain drink, by 1915.
Float.—An ade upon the top of which is floated a layer of grape juice, ginger ale, or in some cases a disher of fruit sherbet or ice cream. In the latter case it would be known as a "sherbet float" or an "ice-cream float." ["The Dispenser's Formulary: Or, Soda Water Guide," New York, 1915]
Few soda water dispensers know what is meant by a "Float Ice Cream Soda." This is not strange since the term is a coined one. By a "float ice cream soda" is meant a soda with the ice cream floating on top, thus making a most inviting appearance and impressing the customer that you are liberal with your ice cream, when you are not really giving any more than the fellow that mixes his ice cream "out of sight." [The Spatula, Boston, July, 1908]