English noun: R | |||
1. | R (quantity) a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air | ||
Synonyms | roentgen | ||
Broader (hypernym) | radioactivity unit | ||
2. | R (quantity) (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole | ||
Synonyms | gas constant, universal gas constant | ||
Broader (hypernym) | constant | ||
Domain category | natural philosophy, physics | ||
3. | R (communication) the 18th letter of the Roman alphabet | ||
Broader (hypernym) | alphabetic character, letter, letter of the alphabet | ||
Member meronym | Latin alphabet, Roman alphabet | ||
4. | r (attribute) the length of a line segment between the center and circumference of a circle or sphere | ||
Synonyms | radius | ||
Broader (hypernym) | length | ||
Narrower (hyponym) | radius of curvature, semidiameter | ||
Part meronym | diam, diameter | ||