(noun) The 18thletter of the modernEnglishalphabet.
(noun)Any of the speechsoundsrepresented by the letterr.
(noun) The 18thin a series.
(noun)Somethingshapedlike the letterR.
(noun) the 18th letter and 14th consonant of the modern English alphabet
(noun) a speech sound represented by this letter, in English usually an alveolar semivowel, as in red
Use "r" in a sentence
"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."
"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)."
"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)."