Center of mass (COM) |
Forces applied to the center of mass will push the body in the direction of the force without causing rotation. |

Compound Collider |
A compound collider is a set of Physics Shapes nested under a single Physics Body. The shapes behave as a single body. |

Convex Radius (Bevel Radius) |
To improve the performance and robustness of collision detection Unity Physics allows contacts to be generated within a small tolerance of the surface of a convex shape. This tolerance is referred to as convex radius or bevel radius. |

Convex shape |
A convex shape or volume has the property that a line segment drawn between any two points inside the volume never leaves the volume. Unity Physics exploits this property to accelerate the performance of collision detection and spatial queries. |

Degree of Freedom (DOF) |
A description of how a linear system is free to move. In rigid body dynamics this usually refers to the 6 degrees of freedom a body has when moving in free space. These are 3 linear and 3 angular degrees of freedom. They correspond to the axes you specify when describing a constraint. |

Inertia Tensor |
Describes the mass distribution of a rigid body. In particular it affects how the angular velocity of a body can change. See Moment of inertia. |

Jacobian |
Typically describes a constraint used during constraint solving. See Jacobian. |