P (named pee ) is the sixteenth  letter of the ISO basic Latin alphabet.

An emoticon is a pictorial representation of a facial expression using punctuation marks and letters, usually written to express a person's mood. Emoticons are often used to alert a responder to the tenor or temper of a statement, and can change and improve interpretation of plain text; emoticons for a smiley face :-) and sad face :-( appear in the first documented use in digital form. The word is a portmanteau word of the English words emotion and icon. In web forums,  instant messengers and online games, text emoticons are often automatically replaced with small corresponding images, which came to be called emoticons as well. Certain complex character combinations can only be accomplished in a double-byte language, giving rise to especially complex forms, sometimes known by their romanized Japanese name of kaomoji.

LOL, an abbreviation for laughing out loud, or laugh out loud, is a common element of Internet slang. It was used historically on Usenet but is now widespread in other forms of computer-mediated communication, and even face-to-face communication. It is one of many initialisms for expressing bodily reactions, in particular laughter, as text, including initialisms for more emphatic expressions of laughter such as LMAO ("laugh(ing) my ass off"), and ROTFL or ROFL ("roll(ing) on the floor laughing"). Other unrelated expansions include the now mostly historical "lots of luck" or "lots of love" used in letter-writing.

Overpressure ammunition, commonly designated as +P or +P+, is small arms ammunition that has been loaded to a higher internal pressure than is standard for ammunition of its caliber (see internal ballistics), but less than the pressures generated by a proof round. This is done typically to produce rounds with a higher muzzle velocity and stopping power, such as ammunition used for defensive purposes. Because of this, +P ammunition is typically found in handgun calibers which might be used for defensive purposes.

P. is an abbreviation or acronym that may refer to:

• Page (paper), where the abbreviation comes from Latin pagina
• Paris Herbarium, at the Muséum national d'histoire naturelle
• Pani (Polish), translating as Mrs.
• The Pacific Reporter
• Pádraig Flynn, a former Irish politician

The PROTON Ontology (PROTo ONtology) is a basic upper-level ontology that contains about 300 classes and 100 properties, providing coverage of the general concepts necessary for a wide range of tasks, including semantic annotation, indexing, and retrieval of documents.

Pascal is an influential imperative and procedural programming language, designed in 1968–1969 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.

The Pentium III brand refers to Intel's 32-bit x86 desktop and mobile microprocessors based on the sixth-generation P6 microarchitecture introduced on February 26, 1999. The brand's initial processors were very similar to the earlier Pentium II-branded microprocessors. The most notable difference was the addition of the SSE instruction set (to accelerate floating point and parallel calculations), and the introduction of a controversial serial number embedded in the chip during the manufacturing process.

The number ( ) is a mathematical constant that is the ratio of a circle's circumference to its diameter. The constant, sometimes written pi, is approximately equal to 3.14159. It has been represented by the Greek letter "" since the mid-18th century. is an irrational number, which means that it cannot be expressed exactly as a ratio of two integers (such as 22/7 or other fractions that are commonly used to approximate ); consequently, its decimal representation never ends and never repeats. It is a transcendental numbera number that cannot be produced with a finite sequence of algebraic operations (powers, sums, and products). The transcendence of implies that it is impossible to solve the ancient challenge of squaring the circle. The digits in the decimal representation of appear to be random, although no proof of this supposed randomness has yet been discovered.

Pi, or is the mathematical constant equal to a circle's circumference divided by its diameter.

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself. A natural number greater than 1 that is not a prime number is called a composite number. For example, 5 is prime, as only 1 and 5 divide it, whereas 6 is composite, since it has the divisors 2 and 3 in addition to 1 and 6. The fundamental theorem of arithmetic establishes the central role of primes in number theory: any integer greater than 1 can be expressed as a product of primes that is unique up to ordering. This theorem requires excluding 1 as a prime.

The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number. The name proton was given to the hydrogen nucleus by Ernest Rutherford in 1920, because in previous years he had discovered that the hydrogen nucleus (known to be the lightest nucleus) could be extracted from the nuclei of nitrogen, and was thus a candidate to be a fundamental particle and building block of all complex atomic nuclei.

(majuscule: , minuscule: ) is a Latin P with a diacritical tilde. It is or was used as a grapheme in some languages of Vanuatu, such as North Efate, South Efate and Namakura, to represent a .

The sound recording copyright symbol, represented by the graphic symbol ℗ (a circled P), is the copyright symbol used to provide notice of copyright in a sound recording (phonogram). The use of the symbol originated in United States copyright law and is specified internationally in the Convention for the Protection of Producers of Phonograms Against Unauthorized Duplication of Their Phonograms.

The peseta (; ; ; , or ; , ) was the currency of Spain between 1869 and 2002. Along with the French franc, it was also a de facto currency used in Andorra (which had no national currency with legal tender).

In mathematics, Weierstrass's elliptic functions are elliptic functions that take a particularly simple form; they are named for Karl Weierstrass. This class of functions are also referred to as P-functions and generally written using the symbol P (or ), and known as "Weierstrass P").