R (minuscule: ) is a letter of the Slovak and Lower Sorbian alphabets. It is formed from R with the addition of an acute. Their Unicode codepoints are and . The PS names are Racute and racute.

The grapheme R, r (R with hácek, example of Czech pronunciation: ) is a letter used in alphabets of the Czech, Upper Sorbian, and Silesian languages. A similar consonant can also be found in some Norwegian dialects around Narvik and in Berber (especially in its Rif variety). However, of the official national languages, it has only the Czech language.

R (named ar/or ) is the 18th letter of the modern English alphabet and the ISO basic Latin alphabet.

A carriage return, sometimes known as a cartridge return and often shortened to CR, <CR> or return, is a control character or mechanism used to reset a device's position to the beginning of a line of text. It is closely associated with the line feed and newline concepts, although it can be considered separately in its own right, as explained further below.

A cedilla ( ; from Spanish), also known as cedilha (from Portuguese) or cédille (from French), is a hook or tail ( ) added under certain letters as a diacritical mark to modify their pronunciation. In Catalan, French, and Portuguese, it is used only under the c, and the entire letter is called respectively c trencada (i.e. "broken C"), "c cédille", and "c cedilhado" (or "c cedilha", colloquially).

A complex number is a number that can be expressed in the form a + bi, where a and b are real numbers and i is the imaginary unit, that satisfies the equation i² = -1. In this expression, a is the real part and b is the imaginary part of the complex number.

D- means:

• Placed before a U.S. state, usually in parentheses, indicates the person it applies to is a Democratic Party politician of that state. "R-" is used for the Republican Party.
• An academic grade given by certain institutions. Slightly better than an F and slightly worse than a D. See Grade (education).
• A prefix signifying chirality of a molecule

The system of hyperreal numbers is a way of treating infinite and infinitesimal quantities. The hyperreals, or nonstandard reals, *R, are an extension of the real numbers R that contains numbers greater than anything of the form

R++ is a rule-based programming language based on C++. The United States patent describes R++ as follows:

The R++ extension permits rules to be defined as members of C++ classes. The programming system of the invention takes the classes with rules defined using R++ and generates C++ code from them in which the machinery required for the rules is implemented completely as C++ data members and functions of the classes involved in the rules.

R. is an abbreviation of the Latin word Rex (King) or Regina (Queen).

In mathematics, a real number is a value that represents a quantity along a continuous line. The adjective real in this context was introduced in the 17th century by Descartes, who distinguished between real and imaginary roots of polynomials.

The registered trademark symbol (®) is a symbol that provides notice that the preceding word or symbol is a trademark or service mark that has been registered with a national trademark office. A trademark is a symbol, word, or words legally registered or established by use as representing a company or product.. Notwithstanding the symbol doesn't meet the threshold of originality to be protected by copyright because it consists only in a capital letter rounded by a simple geometric shape, in some countries it is against the law to use the registered trademark symbol for a mark that is not officially registered in any country.

In the branch of mathematics known as real analysis, the Riemann integral, created by Bernhard Riemann, was the first rigorous definition of the integral of a function on an interval. For many functions and practical applications, the Riemann integral can be evaluated by the fundamental theorem of calculus or approximated by numerical integration.