| Symbol | Description |
| A | area |
| CD | drag coefficient |
| CL | lift coefficient |
| D | diameter |
| E | Young's modulus, energy |
| FD | drag force |
| FL | lift force |
| G | modulus of rigidity, gravitational constant |
| HB | Brinell hardness |
| Kf | stress concentration factor, fatigue |
| Ks | stress concentration factor, shear |
| Kt | stress concentration factor (normal stresses) |
| Kts | stress concentration factor (shear stresses) |
| P | load, pressure |
| Pf | fracture load |
| R | resistance |
| RB | Rockwell B hardness |
| RC | Rockwell C hardness |
| S'e | endurance limit, rotary-beam test specimen |
| Sa | alternating, or amplitude strength |
| Sc | compressive strength |
| Se | endurance limit, at crit. loc. of mach part (or fatigue limit) |
| Sf | fracture strength, or fatigue strength |
| Sm | midrange, or mean strength |
| Ssy | torsional yield strength |
| St | tensile strength |
| Su | ultimate strength (can also be ultimate tensile strength) |
| Suc | ultimate compressive strength, or compressive strength |
| Sut | ultimate tensile strength, or tensile strength |
| Sy | yield strength |
| Syc | yield compressive strength |
| Syt | yield tensile strength |
| T | temperature |
| a | acceleration |
| cp | specific heat, constant pressure |
| cv | specific heat, constant volume |
| d | diameter, derivative |
| g | gravitational acceleration (or acceleration due to gravity) |
| h | enthalpy |
| i | current |
| k | thermal conductivity |
| ka | modification factor, surface condition |
| kb | modification factor, size |
| kc | modification factor, load |
| kd | modification factor, temperature |
| ke | modification factor, reliability |
| kf | modification factor, miscellaneous effects |
| m | mass |
| n | safety factor |
| nd | design factor |
| p | pressure |
| q | charge, heat |
| r | radius |
| s | entropy |
| t | time |
| u | internal energy, velocity |
| v | specific volume, velocity, voltage |
| w | energy, work |
| γ | shear strain |
| δ | elongation |
| ε | emissivity, normal strain |
| μ | viscosity |
| ν | Poisson's ratio |
| ρ | density |
| σ | normal stress, Stefan-Boltzmann constant |
| σN | fatigue limit |
| σa | amplitude stress |
| σf | true fracture stress |
| σm | mean stress |
| σr | range of stress |
| σu | true ultimate stress |
| τ | shear stress |
| ω | angular velocity |
| ∈ | normal strain |