"one who refuses obedience to a superior or controlling power or principle; one who resists an established government; person who renounces and makes war on his country for political motives," mid-14c., originally in reference to rebellion against God, from rebel (adj.).
By mid-15c. in the general sense of "obstinate or refractory person." The meaning "supporter of the American cause in the War of Independence" is by May 1775; sense of "supporter of the Southern cause in the American Civil War" is attested from April 15, 1861.
The Civil War's rebel yell is attested from 1862, but the thing itself is older and was said to have been picked up by (then) southwestern men in their periodic wars against the Indians.
The Southern troops, when charging or to express their delight, always yell in a manner peculiar to themselves. The Yankee cheer is more like ours; but the Confederate officers declare that the rebel yell has a particular merit, and always produces a salutary and useful effect upon their adversaries. A corps is sometimes spoken of as a 'good yelling regiment.' [A.J.L. Fremantle, "The Battle of Gettysburg and the Campaign in Pennsylvania," in Blackwood's Edinburgh Magazine, Sept. 1863]
Rebel without a cause is from the title of the 1955 Warner Bros. film, a title said to have been adopted from psychiatrist Robert M. Linder's 1944 classic "Rebel Without a Cause," which follows the successful analysis and hypnosis of a criminal psychopath but otherwise has nothing to do with the movie.
c. 1400, "avowal, pledge, solemn declaration," from Old French protest, from protester, from Latin protestari "declare publicly, testify, protest," from pro- "forth, before" (from PIE root *per- (1) "forward," hence "in front of, before") + testari "testify," from testis "witness" (see testament).
Meaning "statement of disapproval" is recorded by 1751. By late 19c. this was mostly restricted to "a solemn or formal declaration against some act or course of action."
The adjectival sense of "expressing of dissent from, or rejection of, prevailing social, political, or cultural mores" is by 1942, in reference to U.S. civil rights movement (in protest march); protest rally from 1960. Protest vote, "vote cast to demonstrate dissatisfaction with the choice of candidates or the current system," is by 1905 (in reference to Socialist Party candidates).
Because they now fully understood the power of the picket line, they were ready and anxious to march on Washington when A. Philip Randolph, president of the Brotherhood of Sleeping Car Porters, advanced the idea in January 1941 of organizing a Negro protest march on Washington, because Government officials from the President down to minor bureau chiefs, had persistently evaded the issue of combating discrimination in defense industries as well as the Government itself. As the time for the event drew nearer some of the heads of the Government became alarmed; Randolph reported that a ranking New Dealer had told him many Government officials were asking, "What will they think in Berlin?" [Statement of Edgar G. Brown, Revenue Revision of 1942 hearings, 77th Congress, 2nd session]
Middle English seien, from Old English secgan "to utter, inform, speak, tell, relate," from Proto-Germanic *sagjanan "to say" (source also of Old Saxon seggian, Old Norse segja, Danish sige, Old Frisian sedsa, Middle Dutch segghen, Dutch zeggen, Old High German sagen, German sagen "to say").
Watkins has this from a PIE *sokwyo-, from a root *sekw- (3) "to say, utter" (source also of Hittite shakiya- "to declare," Lithuanian sakyti "to say," Old Church Slavonic sociti "to vindicate, show," Old Irish insce "speech," Old Latin inseque "to tell say"). Some further see this as identical to the PIE root *sekw- (1) "to follow" (with semantic development to "see" and then "speak"). But others doubt it and Boutkan gives it "No certain PIE etymology."
The past tense form said developed from Old English segde. Impersonal use (it is said) was in Old English. The notion in shall we say, etc. (1580s) is "suppose, take for granted." On that analogy, impersonal say is used as an introduction word, or parenthetically, with a clause and meaning "suppose, assume" (c. 1600). Its colloquial use as an expression of surprise, etc. is by 1830.
Not attested before 1930 in use with inanimate objects (clocks, signs, etc.) as subjects. You said it! "you're right" is attested by 1919; you can say that again as a phrase expressing agreement is recorded from 1942, American English colloquial. You don't say(so) as an expression of astonishment (often ironic) is attested by 1779. The Society of American Florists' advertising slogan say it with flowers dates to 1918 from it grew other say it with constructions.
Old English deaþ "total cessation of life, act or fact of dying, state of being dead; cause of death," in plural, "ghosts," from Proto-Germanic *dauthuz (source also of Old Saxon doth, Old Frisian dath, Dutch dood, Old High German tod, German Tod, Old Norse dauði, Danish død, Swedish död, Gothic dauus "death"), from verbal stem *dau-, which is perhaps from PIE root *dheu- (3) "to die" (see die (v.)). With Proto-Germanic *-thuz suffix indicating "act, process, condition."
I would not that death should take me asleep. I would not have him meerly seise me, and onely declare me to be dead, but win me, and overcome me. When I must shipwrack, I would do it in a sea, where mine impotencie might have some excuse; not in a sullen weedy lake, where I could not have so much as exercise for my swimming. [John Donne, letter to Sir Henry Goodere, Sept. 1608]
Of inanimate things, "cessation, end," late 14c. From late 12c. as "death personified, a skeleton as the figure of mortality." As "a plague, a great mortality," late 14c. (in reference to the first outbreak of bubonic plague; compare Black Death). Death's-head, a symbol of mortality, is from 1590s. Death's door "the near approach of death" is from 1540s.
As a verbal intensifier "to death, mortally" (as in hate (something) to death) 1610s; earlier to dead (early 14c.). Slang be death on "be very good at" is from 1839. To be the death of "be the cause or occasion of death" is in Shakespeare (1596). Expression a fate worse than death is from 1810 though the idea is ancient.
Death row "part of a prison exclusively for those condemned to capital execution" is by 1912. Death knell is attested from 1814; death penalty "capital punishment" is from 1844; death rate from 1859. Death-throes "struggle which in some cases accompanies death" is from c. 1300.
"quadruped of the genus Canis," Old English docga, a late, rare word, used in at least one Middle English source in reference specifically to a powerful breed of canine; other early Middle English uses tend to be depreciatory or abusive. Its origin remains one of the great mysteries of English etymology.
The word forced out Old English hund (the general Germanic and Indo-European word, from root from PIE root *kwon-) by 16c. and subsequently was picked up in many continental languages (French dogue (16c.), Danish dogge, German Dogge (16c.)). The common Spanish word for "dog," perro, also is a mystery word of unknown origin, perhaps from Iberian. A group of Slavic "dog" words (Old Church Slavonic pisu, Polish pies, Serbo-Croatian pas) likewise is of unknown origin.
In reference to persons, by c. 1200 in abuse or contempt as "a mean, worthless fellow, currish, sneaking scoundrel." Playfully abusive sense of "rakish man," especially if young, "a sport, a gallant" is from 1610s. Slang meaning "ugly woman" is from 1930s; that of "sexually aggressive man" is from 1950s.
Many expressions — a dog's life (c. 1600), go to the dogs (1610s), dog-cheap (1520s), etc. — reflect the earlier hard use of the animals as hunting accessories, not pets. In ancient times, "the dog" was the worst throw in dice (attested in Greek, Latin, and Sanskrit, where the word for "the lucky player" was literally "the dog-killer"), which plausibly explains the Greek word for "danger," kindynos, which appears to be "play the dog" (but Beekes is against this).
Notwithstanding, as a dog hath a day, so may I perchance have time to declare it in deeds. [Princess Elizabeth, 1550]
Meaning "something poor or mediocre, a failure" is by 1936 in U.S. slang. From late 14c. as the name for a heavy metal clamp of some kind. Dog's age "a long time" is by 1836. Adjectival phrase dog-eat-dog "ruthlessly competitive" is by 1850s. Phrase put on the dog "get dressed up" (1934) may be from comparison of dog collars to the stiff stand-up shirt collars that in the 1890s were the height of male fashion (and were known as dog-collars from at least 1883).
And Caesar's spirit, ranging for revenge,
With Ate by his side come hot from Hell,
Shall in these confines with a monarch's voice
Cry Havoc! and let slip the dogs of war;
[Shakespeare, "Julius Caesar"]