# Definitions and Synonyms of *r* | Another word for *r* | What is *r? *

*Definition 1: the length of a line segment between the center and circumference of a circle or sphere - [noun denoting attribute]*

*Synonyms for r in the sense of this definition*

*(**r* is a kind of ...) the linear extent in space from one end to the other; the longest dimension of something that is fixed in place

*r*is a kind of ...) the linear extent in space from one end to the other; the longest dimension of something that is fixed in place

### (... is a kind of

### (... is a kind of

### (... is part of

*"the length of the table was 5 feet"*### (... is a kind of *r* ) the apparent radius of a celestial body when viewed as a disc from the earth

### (... is a kind of *r* ) the radius of the circle of curvature; the absolute value of the reciprocal of the curvature of a curve at a given point

### (... is part of *r*) the length of a straight line passing through the center of a circle and connecting two points on the circumference

*Definition 2: the 18th letter of the Roman alphabet - [noun denoting communication]*

*(**r* is a kind of ...) the conventional characters of the alphabet used to represent speech

*r*is a kind of ...) the conventional characters of the alphabet used to represent speech

### (... is a member of

*"his grandmother taught him his letters"*### (... is a member of *r*) the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europe

*Definition 3: a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air - [noun denoting quantity]*

*Synonyms for r in the sense of this definition*

*(**r* is a kind of ...) a measure of radioactivity

*r*is a kind of ...) a measure of radioactivity

*Definition 4: (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole - [noun denoting quantity]*

*Synonyms for r in the sense of this definition*

*(**r* is a kind of ...) a number representing a quantity assumed to have a fixed value in a specified mathematical context

*r*is a kind of ...) a number representing a quantity assumed to have a fixed value in a specified mathematical context

*"the velocity of light is a constant"**(r* belongs to category ...) the science of matter and energy and their interactions

*"his favorite subject was physics"*