R
R is the eighteenth letter of the Latin alphabet.
Semitic Rêš (the head) developed into Greek Ρω (Rô). The sound value /r/ however was maintained in Greek as well as Etruscan and Latin.
Romeo represents the letter R in the NATO phonetic alphabet.
Meanings for R
- In biochemistry, R is the symbol for arginine.
- In calendars, R is often used as an abbreviation for Thursday instead of T, to avoid confusion with Tuesday.
- In chemistry,
- in chess, R is a notation symbol for the rook piece
- In commerce, R with an enclosing circle, ®, denotes a registered trademark.
- In computing, R is the name of a statistical programming language; see R (programming language)
- In electrical engineering, R is often the variable for electrical resistance
- In film, R is a rating given for films given by the Motion Picture Association of America; see R (rating)
- In financial securities, R is the stock symbol for Ryder Systems Inc.
- In geometry, r is often a variable for the radius of a circle
- In law, R stands for Rex (king) or Regina (queen) in court citations in countries that recognize the British monarch as head of state.
- In mathematics, blackboard bold <math>\mathbb{R}<math> represents the real numbers
- In navigation, R denotes the relative direction "right"; see left and right.
- In physics, R is the symbol for roentgen, a unit of dosage of X-rays or gamma radiation.
- In radiocommunication, R is one of the ITU prefixes allocated to Russia.
See also: Uvular R, Я
Two-letter combinations starting with R:
