P

Encyclopedia : P : P : P : P

Latin alphabet
	Aa	Bb	Cc	Dd
Ee	Ff	Gg	Hh	Ii	Jj
Kk	Ll	Mm	Nn	Oo	Pp
Qq	Rr	Ss	Tt	Uu	Vv
	Ww	Xx	Yy	Zz

The letter P is the sixteenth letter in the Latin alphabet. Its name in English is pee /piː/.

Semitic Pê (mouth) as well as Greek Π or π (Pi) and the Etruscan and Latin letters that developed from the former alphabet all symbolized /p/, a plosive, unvoiced consonant. Those who speak Arabic usually have difficulty pronouncing this sound; they pronounce it like B instead.

Contents

1 Phonetic use
2 Codes for computing
3 Meanings for P
4 See also

Phonetic use

In English and most other European languages, P is a voiceless bilabial plosive (/p/ in the IPA). A common digraph in English is "ph", which represents the voiceless labiodental fricative /f/, and is commonly used to transliterate Phi ( φ ) in loanwords from Greek. Both initial and final P can be combined with many other discrete consonants in English words. A common example of assimilation is the tendency of prefixes ending in N to become M before P (such as "in" + "pulse" → "impulse" — see also List of Latin words with English derivatives).

In German, the digraph "pf" is common, representing a labial affricate of /p/ and /f/.

Codes for computing

Alternative representations for

NATO phonetic		Morse code
Papa		[·– –·]

Signal flag	Semaphore	ASL Manual	Braille

In Unicode the capital P is codepoint U+0050 and the lowercase p is U+0070.

The ASCII code for capital P is 80 and for lowercase p is 112; or in binary 01010000 and 01110000, respectively.

The EBCDIC code for capital P is 215 and for lowercase p is 151.

The numeric character references in HTML and XML are "P" and "p" for upper and lower case respectively.

Meanings for P

In astronomy,
* P stands for the planet Pluto; for example, S/2005 P 1 is the first satellite of Pluto sighted in 2005.
* P stands for periodic (comet), as in 1P/Halley or 173P/Mueller.
* P stands for an August 1 through 15 discovery, in the provisional designation of a comet (e.g. C/1957 P1, Comet Mrkos) or asteroid (e.g. (4034) 1986 PA).
In baseball, P is the abbreviation for the position of pitcher.
In bibliography, p (or p.) is the abbreviation for page (pp. stands for "pages").
In biochemistry, P is the symbol for proline.
In chemistry, P is the symbol for the element phosphorus, or sometimes for phosphate.
In chess, P is sometimes used as a notation symbol for the pawn piece
In computer science,
* P is an operation on a semaphore, used for process synchronisation.
* In complexity theory, P is the set of decision problems solvable in polynomial time on a deterministic Turing machine
In computing, <p> is the HTML tag to mark the beginning of paragraphs.
In driving a motor vehicle, P designates the parking gear of an automatic transmission.
In economics, P is usually used to represent price levels.
In electronics, a p type (or p-type) semiconductor has been doped in order to increase the number of positive (hence the p) charge carriers.
In international licence plate codes, P stands for Portugal.
In mathematics, blackboard bold [\mathbb] represents the set of all prime numbers, while p is usually a variable representing a single arbitrary prime number.
In metrology,
* P is the symbol for the French foot (pied);
* p is the symbol for the French inch (pouce); and
* p can also stand for "part", as in ppm ("parts per million").
In music, p stands for piano, meaning "softly" (pp stands for "pianissimo").
In New Zealand P is slang for pure methamphetamine.
In photography, most SLR cameras use P to signify program mode, where the camera sets both aperture and shutter speed.
In physics,
* p is the symbol for momentum or pressure
* P is the symbol for power or polarisation;
* P is the symbol for the poise, the CGS unit of dynamic viscosity;
* p is the symbol for the poncelet, an obsolete unit of power; and
* p is the symbol for the pond, an obsolete unit of force.
* In particle physics, p is the symbol for the proton.
As the first letter of a postal code,
* In Canada, P stands for Northern Ontario.
In probability and statistics,
* p denotes probability
* the p-value of a given result in an experiment is the result's significance; that is, the probability of observing this result or a more extreme result, by chance alone.
In publishing, a circled P, ℗, represents a copyright on a sound recording.
In Roman naming convention, P is the abbreviation for the praenomen Publius.
In the SI system,
* p, pico, is an SI prefix meaning 10^-12
* P, peta, is an SI prefix meaning 10¹⁵
In symbolic logic, p is often used to denote a proposition as well as q and r.
In the United Kingdom,
* In British coinage, p is the symbol for penny (plural pence), for example 25p (25 pence).
* In Regulation of therapeutic goods 'P' designates Pharmacist-only over-the-counter drugs.
In Windows, Ctrl-P, and Mac OS, Command-P, usually prints the open document.

P

Phonetic use

Codes for computing

Meanings for P

See also