| P | Phosphorus |
| Pa | Protactinium |
| palladium | Palladium |
| Pappus's centroid rules | General Rules for 3D Solids |
| parallelepiped | Parallelepiped |
| parallelogram | Parallelogram and Rhombus |
| | Varignon Parallelogram |
| parameters | Earth - Bulk Parameters |
| Parsec | Common Constants in Astronomy |
| Pascal | Common Measurement Units - Force, Pressure, Weight |
| | Common Measurement Units - Derived SI Units |
| Pauli | Wolfgang Ernst Pauli |
| Pb | Lead |
| Pd | Palladium |
| pebi | Prefixes for Binary Multiples |
| perimeter | Ellipse |
| periodic table of the elements | Periodic Table of the Elements |
| permittivity | Dielectric Constant |
| permutation | Matrix Determinant |
| perpendicular bisectors | Circumcircle of a Triangle |
| peta | Order of Magnitude - SI Prefixes |
| pH | pH Value |
| pH indicator | pH Value |
| pH meter | pH Value |
| phosphorus | Phosphorus |
| physical constants | Common Constants in Physics |
| Pi | Common Math Constants |
| pico | Order of Magnitude - SI Prefixes |
| piezoelectric material | Curie Point |
| PiH | Common Math Constants |
| pint | Common Measurement Units - Length, Area & Volume |
| PiSqr | Common Math Constants |
| Pitom1 | Common Math Constants |
| Planck | Max Planck |
| Planck constant | Common Constants in Physics |
| Planck's law | Planck's Radiation Law |
| platinum | Platinum |
| platykurtic distribution | Kurtosis |
| plutonium | Plutonium |
| Pm | Prometium |
| Po | Polonium |
| pOH | pOH Value |
| point | Common Measurement Units - Length, Area & Volume |
| point mirroring | Coordinate Transform |
| Poisson distribution | Poisson Distribution |
| polar coordinate system | Two-dimensional Polar Coordinate System |
| | Conversion between Polar and Cartesian Coordinates |
| polar radius | Earth - Bulk Parameters |
| polonium | Polonium |
| polynomials | Polynomials |
| pork | Pork |
| potassium | Potassium |
| pound | Common Measurement Units - Force, Pressure, Weight |
| poundal | Common Measurement Units - Force, Pressure, Weight |
| power units | Common Measurement Units - Light, Power, Energy |
| Powers | Powers |
| Pr | Praseodymium |
| praseodymium | Praseodymium |
| prefixes | Order of Magnitude - SI Prefixes |
| | Prefixes for Binary Multiples |
| preservatives | Preservatives |
| pressure units | Common Measurement Units - Force, Pressure, Weight |
| prime number | Prime Number |
| principal diagonal | Matrix Algebra - Fundamentals |
| prism | Prism |
| production of ammonia | Production of Ammonia |
| prometium | Prometium |
| properties of a right triangle | Properties of a Right Triangle |
| properties of ammonia | Properties of Ammonia |
| protactinium | Protactinium |
| proton | Common Constants in Physics |
| pseudo-inverse matrix | Moore-Penrose Pseudo-Inverse Matrix |
| psi | Common Measurement Units - Force, Pressure, Weight |
| Pt | Platinum |
| Ptolemy's theorem | Cyclic Quadrilateral |
| Pu | Plutonium |
| pyramid | Pyramid |
| pyramidal frustum | Pyramidal Frustum |
| Pythagorean Theorem | Pythagorean Theorem |
| | Generalized Pythagorean Theorem |
