from The American Heritage® Dictionary of the English Language, 5th Edition.

  • abbreviation radius
  • abbreviation Electricity resistance
  • noun The 18th letter of the modern English alphabet.
  • noun Any of the speech sounds represented by the letter r.
  • noun The 18th in a series.
  • noun Something shaped like the letter R.

from The Century Dictionary.

  • noun An abbreviation of Right Worshipful; Right Worthy.
  • noun An abbreviation of Rear-Admiral;
  • noun of Royal Arcanum;
  • noun of Royal Artillery (also R. Art.).
  • noun An abbreviation of Red Cross
  • noun [lowercase] of right center.
  • noun An abbreviation of rapid fire;
  • noun in mineralogy, of reducing flame;
  • noun [capitalized] of République Française, French Republic;
  • noun [capitalized] of Rex Francorum, King of the Franks (French).
  • An abbreviation of Radical;
  • of railway;
  • [lowercase] of rare;
  • [lowercase or cap.] of read;
  • of Réaumur (see thermometer);
  • of rector;
  • of Republican;
  • [lowercase] of residence and resides;
  • of response;
  • of the Latin Respublica, ‘the Republic’;
  • [lowercase or cap.] of retired;
  • of river;
  • [lowercase or cap.] of rod or rods;
  • of Roma, Rome;
  • [lowercase or cap.] of rood or roods;
  • [lowercase] in geometry, of radius (of the incircle); r1, r2, r3, denote the ex-radii beyond a, b, c, respectively; R denotes the radius of the circumcircle;
  • [capitalized] in psychophysics, an abbreviation of G. Reiz, stimulus.
  • As a symbol: In chem., R has been used for rhodium: more generally, Rh.
  • In elect., R or r denotes resistance.
  • In electrotechnics, r stands for radius.
  • An abbreviation of Rifle Volunteers.
  • An abbreviation of railway. Also Rw.
  • noun An abbreviation of Royal Engineers;
  • noun of Royal Exchange.
  • noun An abbreviation of Reformed Episcopal
  • noun of Right Excellent
  • noun [lowercase] of right eye.
  • noun An abbreviation of Royal Dragoons;
  • noun of Rural Dean.
  • noun An abbreviation of Roman Catholic.
  • noun An abbreviation of Revised Version (of the Bible).
  • noun An abbreviation of Rhode Island.
  • noun An abbreviation of railroad.
  • The eighteenth letter and fourteenth consonant in the English alphabet, representing a character having a like position and value in the alphabets from which the English is derived—the Latin, Greek, and Phenician.


from Wiktionary, Creative Commons Attribution/Share-Alike License

Modification of capital letter R by not closing the bottom of the loop but continuing into the leg to save a pen stroke, later shortening the right leg into a simple arc.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From are, pronounced like the name of the letter r


  • An uncharged black hole has no inner horizon; it should come as no surprise, then, that as you increase the charge (keeping the mass of the black hole fixed), the two horizons at r+ and r - come together.

    Where Does the Entropy Go?

  • Also take the quantities q, q², r, r² of the above lemma (11) to be the single expectation values:

    Bell's Theorem

  • [0, X], and r, r², are real numbers such that r and r² fall in the closed interval

    Bell's Theorem

  • In an extremal black hole, where all of the energy comes from the electric field itself, the two horizons coincide: we have r+ = r - (extremality).

    Where Does the Entropy Go?

  • A representation r is maximally consistent if and only if r is consistent and for any representation r², either r & not-r² is not consistent or r & r² is not consistent (assuming the appropriate conceptions of the negation and conjunction of representations).

    Possible Objects

  • She ate her dinner quite contentedly, and was just going to settle down comfortably to some thrilling tale of adventure when Br -- r-- r! went the bell, and she knew her fate had descended upon her.

    The Governess

  • _Fa-rewe ` ll lo-ue a ` nd a-ll thi ` e la-wes fo ` r e-ve ` r_

    The Arte of English Poesie

  • This rule is conveniently expressed by the formula ((x + 9)/28) _r, in which x denotes the date, and the symbol r denotes that the remainder, which arises from the division of x + 9 by 28, is the number required.

    Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary"

  • He commences slowly, as if repeating the syllable, _de de de de de de d 'd' d 'd' d 'd' d 'r' r 'r'_, -- increasing in rapidity, and at the same time rising as it were by semi-tones, or chromatically, to about a major fourth on the scale.

    The Atlantic Monthly, Volume 2, No. 14, December 1858

  • The air is full of the rattle of the cicada, which is like the sound of a loud cricket, or the 'r-- r' of a corncraik's note going on for ever and ever; and the house lizard in the church goes cheep -- cheep -- cheep every now and then.

    From Edinburgh to India & Burmah


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