R
WordNet
noun
(1) The length of a line segment between the center and circumference of a circle or sphere
(2) The 18th letter of the Roman alphabet
(3) (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole
(4) A unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air
WiktionaryText
Etymology 1
Modification of capital letter 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.
Letter
- The eighteenth letter of the basic modern Latin alphabet.
See also
® ℝ ɻ r̃ Cyrillic , Greek , Hebrew , Hangeul
- dog's letter
Symbol
- radius
- used in the International Phonetic Alphabet and in several romanization systems of non-Latin scripts to represent an alveolar trill ([r]) or various other rhotic sounds (/r/).
Etymology 1
lower case letter , from 7th century replacement by Latin lower case of the Anglo-Saxon Futhorc letter .
Letter
- The letter ar, the eighteenth letter of the English alphabet.
Verb
- are.
- How r u — “How are you?”
Letter
- The eighteenth letter of the Dutch alphabet.