• P (peta) = 1E+15 (prefix)
• p (pico) = 0.000000000001 (prefix)
• P = poise (dynamic viscosity)
• Pa = pascal (pressure)
• pace = 30 in (length)
• palm = 3 in (length)
• parasang = 3.5 mile (length)
• parsec = au*rad/arc sec (length; derived unit)
• pascal = N/m^2 (pressure; derived unit)
• pc = parsec (length)
• pdl = poundal (force)
• peck (dry peck) = 2 dry gallon (volume)
• pennyweight = pennyweight troy (mass)
• pennyweight troy (troy pennyweight) = 24 grain (mass)
• per (" per ") = "/"
• percent = 0.01
• perch = rod (length)
• perennial = yr (time)
• perigon = circle (plane angle)
• Permeability
  • magnetic field (constant) = 0.0000004 pi*H/m
  • magnetic permeability = permeability
  • permeability = H/m (category unit)
  • u0 = magnetic field
• permeability = H/m (permeability; category unit)
• permeability2 = area (area)
• permeance = inductance (inductance)
• Permittivity
  • dialectric permittivity = permittivity
  • dialectric strength = permittivity
  • electric field (constant) = 8.8542E-12 F/m
  • epsilon0 = electric field
  • permittivity = F/m (category unit)
• permittivity = F/m (permittivity; category unit)
• peta = 1E+15 (prefix)
• petroleum barrel = 42 gallon (volume)
• pfund (German pfund) = 500 gram (mass)
• ph = phot (luminance)
• phot = cd/cm^2 (luminance; derived unit)
• pi = 3.14159265358979
• pica (typography pica) = 0.166666666666667 in (length)
• pico = 0.000000000001 (prefix)
• picul (Chinese picul) = 100 catty (mass)
• pieze = 1000 Pa (pressure)
• pint (fluid pint) = 0.5 quart (volume)
• pipe = 2 hogshead (volume)
• pitch = frequency (frequency)
• pk = peck (volume)
• planck (Planck constant) = 6.626196E-34 J*s (angular momentum)
• Plane Angle
  • arc deg = degree
  • arc degree = degree
  • arc min = arc minute
  • arc minute (minute of arc) = 1.66666666666667E-02 arc degree
  • arc s (second of arc) = 1.66666666666667E-02 arc minute
  • arc sec = arc s
  • arc second = arc s
  • centesimal minute = 0.01 grade
  • centesimal second = 0.0001 grade
  • circle = 2 pi*rad
  • deg = degree
  • degree (Pi rad / 180) = 1.74532925199433E-02 rad
  • grad = grade
  • grade = 0.015707963267949 rad
  • octant = 0.25 pi*rad
  • perigon = circle
  • plane angle = rad (category unit)
  • quadrant = 0.5 pi*rad
  • r = rad
  • rad (radian) = rad (base unit)
  • radian = rad
  • rev = revolution
  • revolution = 2 pi*rad
  • sextant = 0.333333333333333 pi*rad
  • sign = 0.166666666666667 pi*rad
  • turn = 2 pi*rad
• plane angle = rad (plane angle; category unit)
• point (typography point) = 0.013837 in (length)
• poise = gram/cm*s (dynamic viscosity; derived unit)
• polar moment of inertia of area = moment of inertia of area (moment of inertia of area)
• polar moment of inertia of mass = moment of inertia (moment of inertia)
• polar moment of inertia of volume = moment of inertia of volume (moment of inertia of volume)
• pole = rod (length)
• pondus (Roman pondus) = as (mass)
• pony = 0.5 jigger (volume)
• pood (Russian pood) = 36.11 pound (mass)
• potential = electric potential (electric potential)
• potential difference = electric potential (electric potential)
• pound (avoirdupois pound) = 0.45359237 kg (mass)
• pound ap (apothecary pound) = 12 oz ap (mass)
• pound force = pound*g (force; derived unit)
• pound t = pound troy (mass)
• pound troy (troy pound) = 12 oz troy (mass)
• poundal = ft*pound/s^2 (force; derived unit)
• Power
  • acoustical power = power
  • electrical power = power
  • heat flow rate = power
  • horsepower = 550 ft*pound*g/sec
  • hp = horsepower
  • linear power = power
  • lusec = 0.000001 torr*m^3/s
  • mechanical power = power
  • power = W (category unit)
  • radiant flux = power
  • radiant power = power
  • W = watt
  • watt = J/s (derived unit)
• power = W (power; category unit)
• power to area = heat flux density (heat flux density)
• PREFIXES
  • a (atto) = 1E-18
  • atto = 1E-18
  • bi = 2
  • billion = 1000000000
  • c (centi) = 0.01
  • centi = 0.01
  • centimilli = 0.00001
  • cm (centimilli) = 0.00001
  • d (deci) = 0.1
  • D (deka) = 10
  • da (deka) = 10
  • dec = 10
  • deci = 0.1
  • decillion = 1E+33
  • decimilli = 0.0001
  • deka = 10
  • demi = 0.5
  • dm (decimilli) = 0.0001
  • double = 2
  • duodec = 12
  • E (exa) = 1E+18
  • eighth = 0.125
  • exa = 1E+18
  • f (femto) = 0.000000000000001
  • femto = 0.000000000000001
  • G (giga) = 1000000000
  • giga = 1000000000
  • googol = 1E+100
  • h (hecto) = 100
  • half = 0.5
  • hecto = 100
  • hectokilo = 100000
  • hk (hectokilo) = 100000
  • hundred = 100
  • k (kilo) = 1000
  • kilo = 1000
  • M (mega) = 1000000
  • m (milli) = 0.001
  • ma (myria) = 10000
  • mega = 1000000
  • micro = 0.000001
  • milli = 0.001
  • million = 1000000
  • mono = 1
  • mu (micro) = 0.000001
  • myria = 10000
  • n (nano) = 0.000000001
  • nano = 0.000000001
  • nonillion = 1E+30
  • octillion = 1E+27
  • one = 1
  • P (peta) = 1E+15
  • p (pico) = 0.000000000001
  • peta = 1E+15
  • pico = 0.000000000001
  • quadr = 4
  • quadri = 4
  • quadrillion = 1E+15
  • quadruple = 4
  • quarter = 0.25
  • quin = 5
  • quintillion = 1E+18
  • semi = 0.5
  • septillion = 1E+24
  • sesqu = 1.5
  • sesqui = 1.5
  • sex = 6
  • sextillion = 1E+21
  • T (tera) = 1000000000000
  • ten = 10
  • tera = 1000000000000
  • thousand = 1000
  • thrice = 3
  • tri = 3
  • trillion = 1000000000000
  • triple = 3
  • u (micro) = 0.000001
  • undec = 11
  • vic = 20
  • Y (myria) = 10000
• pregnancy = 9 month*approx (time)
• Pressure
  • atm = atmosphere
  • atmosphere = 101325 Pa
  • bar = 100000 Pa
  • barie = 0.1 Pa
  • barye = 0.1 Pa
  • calorific value volume basis = pressure
  • draft = pressure
  • energy density = pressure
  • mmHg (millimeters of mercury) = mm*Hg weight density (derived unit)
  • Pa = pascal
  • pascal = N/m^2 (derived unit)
  • pieze = 1000 Pa
  • pressure = N/m^2 (category unit)
  • psi (pounds per square inch) = pound*g/in^2 (derived unit)
  • radiant energy density = pressure
  • sound pressure = pressure
  • standard atmosphere = atmosphere
  • stress = pressure
  • torr = mm*Hg weight density (derived unit)
  • vacuum = pressure
  • volume basis calorific value = pressure
• pressure = N/m^2 (pressure; category unit)
• pressure drop to length = weight density (weight density)
• product of inertia of area = moment of inertia of area (moment of inertia of area)
• product of inertia of mass = moment of inertia (moment of inertia)
• product of inertia of volume = moment of inertia of volume (moment of inertia of volume)
• proof = 0.005
• proton mass (proton rest mass) = 1.672614E-27 kg (mass)
• psi (pounds per square inch) = pound*g/in^2 (pressure; derived unit)
• pt = pint (volume)

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