R

名词 r:

1. a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air
   同义词：roentgen
2. (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole
   同义词：gas constant, universal gas constant
3. the 18th letter of the Roman alphabet
   同义词：letter r
4. the length of a line segment between the center and circumference of a circle or sphere
   同义词：radius

1. The trilled `r' is produced by vibrating the tongue against the upper teeth.
   发带颤音的r，舌抬向上齿颤动而成。

r 或 R

n.（名词）
【复数】 r`s 或 R`s
The 8th letter of the modern English alphabet.
字母R：现代英语字母表中的第十八个字母
Any of the speech sounds represented by the letterr.
R的读音：由字母r 所代表的读音
The 8th in a series.
序列中的第十八

r
r 2
abbr.（略语）
Or R Mathematics Radius.
或 R 【数学】 Radius.
Or R Electricity Resistance.
或 R 【电学】 Resistance.
Or r. Baseball Run.
或 r. 【棒球】 Run.