rn. the length of a line segment between the center and circumference of a circle or sphere ; Rn. the 18th letter of the Roman alphabet ; Rn. (physics) the universal constant in the gas equation: pressure times volume = R times temperature ; equal to 8.3143 joules per kelvin per mole ; Rn. a unit of radiation exposure ; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air ; R and Bn. a combination of blues and jazz that was developed in the United States by Black musicians ; an important precursor of rock 'n' roll ; R. B. Cattelln. American psychologist (born in England) who developed a broad theory of human behavior based on multivariate research (1905-1998) ; R. Buckminster Fullern. United States architect who invented the geodesic dome (1895-1983) ; R. J. Mitchelln. English aeronautical engineer (1895-1937) ; R.C.adj. of or relating to or supporting Romanism ; R.I.n. a state in New England ; one of the original 13 colonies ; the smallest state ; R.V.n. a motorized wheeled vehicle used for camping or other recreational activities ; RAn. (astronomy) the equatorial coordinate specifying the angle, measured eastward along the celestial equator, from the vernal equinox to the intersection of the hour circle that passes through an object in the sky ; usually expressed in hours and minutes and seconds ; used with declination to specify positions on the celestial sphere ; Ran. ancient Egyptian sun god with the head of a hawk ; a universal creator ; he merged with the god Amen as Amen-Ra to become the king of the gods ; Ran. an intensely radioactive metallic element that occurs in minute amounts in uranium ores ; Rabatn. the capital of Morocco ; located in the northwestern on the Atlantic coast ;
