"right of each citizen to liberty, equality, etc.," 1721, American English, from civil in the sense "pertaining to the citizen in his relations to the organized commonwealth or to his fellow citizens." Specifically of black U.S. citizens from 1866, in reference to the Civil Rights Bill, an act of Congress which conferred citizenship upon all persons born in the United States, not subjects of other powers, "of every race and color, without regard to any previous condition of slavery." Civil Rights Movement in reference to the drive for racial equality that began in U.S. in mid-1950s is attested by 1963.
Rarely are we met with a challenge, not to our growth or abundance, or our welfare or our security, but rather to the values and the purposes and the meaning of our beloved nation. The issue of equal rights for American Negroes is such an issue. And should we defeat every enemy, and should we double our wealth and conquer the stars, and still be unequal to this issue, then we will have failed as a people and as a nation. [Lyndon Johnson, speech introducing Voting Rights Act, March 15, 1965]
1825, "a rendering rational, act of subjection to rational tests or principles," from rationalize + -ation. The specific sense in psychology in reference to subconscious means to justify behavior to make it seem rational or socially acceptable is by 1908.
Of the three works now on our table, the two which we have placed first have these laudable objects in view; an improvement on the former versions of the Psalms as compositions, and the rationalization, if we may so speak, of our Church psalmody. [The British Critic, London, Jan.-June 1825]
1726, from in- (1) "not, opposite of" + describable. Related: Indescribably; indescribability (1797). In same sense, Old English had unasecgendlic. Indescribables for "trousers" (1819) was colloquial in England for a generation or so.
We cannot omit here to state, that, some years since, we recollect a rumour in the gallery [of the House of Commons], that Madame de Staël was sitting, en habit d'homme, in a surtout and military indescribables, listening to the debate, under the protection of Sir J. Macintosh. ["Privileges of Women," in Retrospective Review, London, 1824]
We do not, therefore, consider it any especial merit of a new dictionary, that it contains a large number of words which have not been in its predecessors. Whether those words are merely local or personal, as "equaled," introduced by Dr. Webster, on the usage of his own writing-desk, or such barbarisms as "conversationism" and "educational," tolerated by Dr. Worcester on the very poor authority of the Eclectic Review, they are only to be harbored as a sort of Japanese sailors, or of Kanackas, whom we send away from us as soon as we can. [review of Joseph E. Worcester's "Dictionary of the English Language," Christian Examiner, May 1860]
"consisting of five metrical feet," 1540s, from French pentametre, from Latin pentameter, from Greek pentametros (adj.) "having five measures," from pente "five" (see five) + metron "measure" (from PIE root *me- (2) "to measure"). As a noun from 1580s, "a verse line of five feet;" in ancient prosody "a dactylic dipenthemimeres or combination of two catalectic dactylic tripodies" [Century Dictionary].
The verses we have hitherto examined may be constructed at pleasure of any kind of metre—dactyl, troche, iamb, or anapest. But all at once, we now find this liberty of choice refused. We may write a pentametre verse in iambs only. A most notable phenomenon, significant of much more than I can at present understand,—how much less explain .... [Ruskin, "Elements of English Prosody, for use in St. George's Schools," 1880]