"bag containing feed for a horse, fastened to its head by straps," 1796, from nose (n.) + bag (n.).
Entries linking to nose-bag
nose n.
Middle English nose, from Old English nosu "the nose of the human head, the special organ of breathing and smelling," from Proto-Germanic *nuso- (source also of Old Norse nös, Old Frisian nose, Dutch neus, Old High German nasa, German Nase), from PIE root *nas- "nose."
Used of beaks or snouts of animals from mid-13c.; of any prominent or projecting part supposed to resemble a nose from late 14c. (nose cone in the space rocket sense is from 1949). Meaning "sense of smell" is from mid-14c. Meaning "odor, scent" is from 1894. In Middle English, to have one's spirit in one's nose was to "be impetuous or easily angered" (c. 1400).
Kiv, It could bee no other then his owne manne, that had thrust his nose so farre out of ioynte. ["Barnabe Riche His Farewell to Military Profession," 1581]
To pay through the nose "pay excessively" (1670s) seems to suggest bleeding. Many extended meanings are from the horse-racing sense of "length of a horse's nose," as a measure of distance between two finishers (1908). To turn up one's nose "show disdain, express scorn or contempt" is from 1818 (earlier hold up one's nose, 1570s); a similar notion is expressed in look down one's nose (1907). To say something is under (one's) nose "in plain view, directly in front of one" is from mid-15c. To be as plain as the nose on one's face "very easy to be seen or understood" is from 1590s.
bag n.
"small sack," c. 1200, bagge, probably from Old Norse baggi "pack, bundle," or a similar Scandinavian source. OED rejects connection to other Germanic words for "bellows, belly" as without evidence and finds a Celtic origin untenable. In some senses perhaps from Old French bague, which is also from Germanic.
As disparaging slang for "woman" it dates from 1924 in modern use (but various specialized senses of this are much older, and compare baggage). The meaning "person's area of interest or expertise" is by 1964, from African-American vernacular, from jazz sense of "category," probably via notion of putting something in a bag. The meaning "fold of loose skin under the eye" is by 1867. Related: bags.
To be left holding the bag (and presumably nothing else), "cheated, swindled" is attested by 1793. Many figurative senses, such as the verb meaning "to kill game" (1814) and its colloquial extension to "catch, seize, steal" (1818) are from the notion of the game bag (late 15c.) into which the product of the hunt was placed. This also probably explains modern slang in the bag "assured, certain" (1922, American English).
To let the cat out of the bag "reveal the secret" is from 1760. The source is probably the French expression Acheter chat en poche "buy a cat in a bag," which is attested in 18c. French and explained in Bailey's "Universal Etymological English Dictionary" (1736), under the entry for To buy a pig in a poke as "to buy a Thing without looking at it, or enquiring into the Value of it." (Similar expressions are found in Italian and German; and in English, Wycliffe (late 14c.) has To bye a catte in þo sakke is bot litel charge). Thus to let the cat out of the bag would be to inadvertently reveal the hidden truth of a matter one is attempting to pass off as something better or different, which is in line with the earliest uses in English.
Sir Joseph letteth the cat out of the bag, and sheweth principles inimical to the cause of true philosophy, by wishing to make great men Fellows, instead of wise men ["Peter Pindar," "Peter's Prophecy," 1788]