Is it 'Leg' or 'Limb'?

Even the most ardent defenders of the English language, those who insist that an adverb should never split asunder the sanctity of an infinitive, will occasionally come across some usage advice which will make them say “Oh come on…are you serious?” In the 19th century there was a fine example of linguistic prescriptivism that ran so amuck that pretty much everybody scoffed at it: the idea that one should say limb rather than leg.

We don't know whether it's true that some 19th-century people covered their furniture legs for the sake of modesty. We do know that some 19th-century people thought it was lewd to refer to women as having 'legs'.

It is unclear when exactly this idea began, but it first entered the broader public consciousness in 1839, when the British novelist Frederick Marryat published his A Diary in America, with Remarks on its Institutions. Marryat wrote of an occasion when a young lady with whom he was walking slipped and fell, after which he asked “Did you hurt your leg much?”

She turned from me evidently much shocked, or much offended; and not being aware that I had committed any very heinous offense, I begged to know what was the reason of her displeasure. After some hesitation, she said that as she knew me well, she would tell me that the word leg was never mentioned before ladies.
—Frederick Marryat, A Diary in America, Vol. II, 1839

Marryat also wrote of visiting a seminary for young women, and being astonished when he discovered that the piano had had its, ahem, legs covered with frilled trousers. There has been a certain amount of skepticism about this claim, and many people do not believe that there was any widespread habit of clothing piano legs. As we at Merriam-Webster are not historians of popular culture, we will not weigh in on this matter. However, we do have a significant body of lexical evidence suggesting that the use of leg was frowned upon by some in the 19th and early 20th centuries.

An Englishman, to whom an American woman should say, “I have the rheumatism in one of my limbs,” might inquire, “Which?” if he did not happen to know that many women in this country, in speaking of their sex’s legs to persons of the other sex, call them distinctively limbs, and there drop the subject....
—Richard Meade Bache, Vulgarisms and Other Errors of Speech, 1869

I must say limb for leg, or some refined lady blushes and calls me coarse….
—Walter Franklin Robie, Sex and Life, 1920

Even if the prescription against saying leg was common at the time, mentions of it appear to occur mainly in making fun of, or chastising, people who observed it.

A little girl told her teacher that her grandmother had died and left her mother a “limbacy.” She had been taught to say limb, not leg.
—Ballou’s Pictorial Drawing-Room Companion, 3 Nov. 1855

And now came along one of those severely moral people—the kind who say “limb” instead of leg—and who modestly cover up the “limbs of their pianos—and wrote a piece in the newspaper demanding that she should be “taken out.”
—Courier-Journal (Louisville, KY), 31 Oct. 1872

Public interest would of course go on to build its positive precepts upon this germ; and, through a variety of examples and experiences, the ritual of modesty would grow, until it reached the New England pitch of sensitiveness and range, making us say stomach instead of belly, limb instead of leg, retire instead of go to bed, and forbidding us to call a female dog by name.
—William James, The Popular Science Monthly, 1 Sept. 1887

Persons who are careful to say limb instead of leg suggest a sort of low consciousness.
—The Nashville American (Nashville, TN), 1 Apr. 1907

In a sign of just how much this euphemism was viewed as absurd, one of the 19th century's most nit-picky pickers of nits, the strict grammarian Richard Grant White, thought that using limb instead of leg was beyond the pale.

Limb. — A squeamishness, which I am really ashamed to notice, leads many persons to use this word exclusively instead of leg ... Perhaps these persons think that it is indelicate for a woman to have legs, and that therefore they are concealed by garments, and should be ignored in speech. Heaven help such folk; they are far out of my reach.
—Richard Grant White, Words and Their Uses, 1880