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

  • abbreviation range (surveying)
  • abbreviation Réaumur (scale)
  • abbreviation registered trademark
  • abbreviation Republican
  • abbreviation Ecclesiastical response
  • abbreviation right
  • abbreviation roentgen
  • abbreviation rook (chess)
  • abbreviation Baseball run
  • A trademark for a movie rating indicating that admission will be granted only to persons of or over a certain age, usually 17, unless accompanied by a parent or guardian.
  • The symbol for a hydrocarbon side chain or substituent of variable chemical structure.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun The eighteenth letter of the English alphabet, called ar and written in the Latin script.
  • noun The ordinal number eighteenth, derived from this letter of the English alphabet, called ar and written in the Latin script.
  • noun The eighteenth letter of the basic modern Latin alphabet.
  • noun physics roentgen (unit)
  • noun physics resistance (in electricity)
  • noun genetics IUPAC 1-letter abbreviation for any purine
  • noun biochemistry IUPAC 1-letter abbreviation for arginine
  • abbreviation US politics Republican
  • abbreviation restricted
  • abbreviation reverse
  • abbreviation right (as opposed to left)
  • abbreviation handbells ring
  • abbreviation chess rook
  • abbreviation baseball, cricket The statistic reporting the number of runs scored by a player
  • abbreviation Thursday


from Wiktionary, Creative Commons Attribution/Share-Alike License

This definition is lacking an etymology or has an incomplete etymology. You can help Wiktionary by giving it a proper etymology.


  • It is interesting that the Drake equation has SFR as the first item R* R star, which was originally given by Drake as "the average rate of star formation in the galaxy"

    If the Earth is Rare, We May Not Hear from ET | Universe Today

  • (Anderson was an R-- a very progressive R, and Rolvaag was DFL).

    Minnesota Recount Almost Over -- But Coleman Could Keep A Franken Win Bottled Up For Weeks

  • Recall that a relation R stands to its ancestral R* as the relation is a parent of stands to is an ancestor of.

    Plural Quantification

  • Joynr post 7/31/7 PA 2298 R 297 R% 12.92 H 538 BA 265 bb/pa 9.09 Slg 449.

    In This Town, the Hitting Coach Wears a Red Shirt

  • S among the members of P, everyone conforms to R; everyone expects everyone else to conform to R; everyone has approximately the same preferences regarding all possible combinations of actions; everyone prefers that everyone conform to R, on condition that at least all but one conform to R; everyone would prefer that everyone conform to R², on condition that at least all but one conform to

    Common Knowledge

  • And since we all know who is doing it, we should stop arguing No on Prop R-----it is No on Prop R slamdunk--and get the mayor's office to tell us who this sub one percenter is so he can be out of our goverment for good.

    City Council Stands Up To ACLU on Behalf of LAPD and The City

  • You said Hume and any similarly situated agnostic has a defeater for R, a belief to which he is inclined by nature -- and you added that the rational course for them therefore is to give up belief in R-- provided they have no other information about the reliability of their faculties.

    Warranted Christian Belief

  • We ought to understand that the total interval (0, 1) say, has a probability, but certain point sets in (0, 1), like R or R′, are of type

    Dictionary of the History of Ideas

  • The conclusion (Tornier, Geiringer) is that to the set R (and to R′) no probability can be assigned in a frequency theory.

    Dictionary of the History of Ideas

  • The single “trial” consists of as many draws as needed to decide whether this decimal is rational or not (belongs to R or to R′).

    Dictionary of the History of Ideas


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    January 2, 2010