P4 may refer to:

Computing

Intel Pentium 4 Pentium 4 is a series of single-core CPUs for desktops, laptops and entry-level servers manufactured by Intel. The processors were shipped from November 20, 2000 until August 8, 2008. All Pentium 4 CPUs are based on the NetBurst microarchitect ...

, a processor series shipped from 2000 to 2008 ** The P4 power connector, introduced in the ATX12V 1.0 standard to power these and later CPUs * The i486DX (P4) model of the

Intel 80486 The Intel 486, officially named i486 and also known as 80486, is a microprocessor introduced in 1989. It is a higher-performance follow-up to the i386, Intel 386. It represents the fourth generation of binary compatible CPUs following the Inte ...

microprocessor, introduced in 1989 *

P4 (programming language) P4 is a programming language for controlling packet forwarding planes in networking devices, such as routers and switches. In contrast to a general purpose language such as C or Python, P4 is a domain-specific language with a number of cons ...

, for controlling network data forwarding * P4, the

Perforce Perforce Software, Inc. is an American developer of software used for developing and running applications, including version control software, web-based repository management, developer collaboration, application lifecycle management, web applic ...

software command line client

Media

P4 Radio Hele Norge P4 Radio Hele Norge AS Norway's leading national, private radio station with 24% national market share, about one million daily listeners and two million weekly. P4 Radio Hele Norge operates a nationwide public service-licence, with official req ...

(PFI), a Norwegian radio company ** Kanal 24 (Kanal 4), which acquired the Norwegian P4 channel from PFI *

Sveriges Radio P4 P4 (''pe fyra'') is a national radio channel produced by the Swedish public broadcaster Sveriges Radio. P4 was started in 1987 as a network of regional stations, but national programming was added in 1993 when P3 was relaunched as a specialist you ...

, a Swedish radio channel * ''

Persona 4 is a 2008 role-playing video game by Atlus. It is chronologically the fifth installment in the ''Persona (series), Persona'' series, itself a part of the larger ''Megami Tensei'' franchise, and was released for the PlayStation 2 in Japan in Ju ...

'', a 2008 video game * '' Periphery IV: Hail Stan'', 2019 album by American progressive metal band Periphery

Military

Skaraborg Regiment (armoured) The Skaraborg Regiment (), designation P 4, is a Swedish Army armoured warfare, armoured regiment that traces its origins back to the 16th century. It was converted from an infantry regiment in 1942. The regiment's soldiers were originally recruit ...

, a Swedish army unit, designated P 4 *

Peugeot P4 The P4 is an unarmoured off-road vehicle used by the military of France. It was manufactured by Peugeot but is now manufactured by Panhard. It is to be replaced with the Petit Véhicule Protégé, PVP by Panhard. The P4 is a derivative of the Mer ...

, a French military vehicle

Science

* P4 laboratory, a biosafety level 4 facility * Tetraphosphorus (P₄), an allotrope of phosphorus * Group p4, the plane symmetry group wallpaper group ''p''4 *

Progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...

(Pregn-4-ene-3,20-dione), a steroid hormone * Kerberos, the fourth moon of Pluto *

Perfect fourth A fourth is a interval (music), musical interval encompassing four staff positions in the music notation of Western culture, and a perfect fourth () is the fourth spanning five semitones (half steps, or half tones). For example, the ascending int ...

, a musical interval * Enterobacteria phage P4 * P4, an EEG electrode site according to the 10-20 system * P4 cell, a stage in the ''Caenorhabditis elegans'' embryonic development *

P4-metric P4 metric (also known as FS or Symmetric F ) enables performance evaluation of the binary classifier. It is calculated from precision, recall, specificity and NPV (negative predictive value). P4 is designed in similar way to F1 metric, however ...

, in statistics, a performance metric

Roads

* P4 road (Latvia) *

P04 road (Ukraine) road is a state regional road in Ukraine connecting the capital of Ukraine, Kyiv and town Zvenyhorodka in Cherkasy Oblast. It is long. The route starts in Kyiv, goes through Fastiv, Bila Tserkva, Tarashcha and ends in Zvenyhorodka. See also ...

Other uses

Papyrus 4 Papyrus 4 (, part of ''Suppl. Gr.'' 1120) is an early List of New Testament papyri, New Testament papyrus of the Gospel of Luke in Greek language, Greek. Opinions differ as to its age. It has been dated anywhere from the late second century to th ...

, a New Testament manuscript *

Trans-Pacific Strategic Economic Partnership The Trans-Pacific Strategic Economic Partnership Agreement (TPSEP), also known as P4, is a trade agreement between four Pacific Rim countries concerning a variety of matters of economic policy. The agreement was signed by Brunei, Chile, Singapore ...

, or P4, a free trade agreement between Brunei, Chile, New Zealand, and Singapore *

Prussian P 4 The Prussian P 4 was a derivative of the P 4.1 (Hanover variant) and the second superheated steam locomotive in the world. Design The engine was based on that of the Class P 4.1 that had Hanomag had produced in large numbers si ...

, a German steam locomotive *

Protofour Protofour or P4 is a set of standards for model railways allowing construction of models to a scale of 4 mm to (1:76.2), the predominant scale of model railways of the British prototype. For historical reasons almost all manufacturers of Bri ...

, or P4, a set of standards for model railways