3ds Max uses a family-tree analogy to describe the relationship between objects linked together in a hierarchy.

Parent

An object that controls one or more children. A parent object is often controlled by another superior parent object.

Child

An object controlled by its parent. A child object can also be a parent to other children. An object that doesn't have any parent is by default a child of the world. (The "world" is an imaginary object that acts as the root of all other objects in the scene.)

Ancestors

The parent and all of the parent's parents of a child object.

Descendents

The children and all of the children's children of a parent object.

Hierarchy

The collection of all parents and children linked together in a single structure.

Root

The single parent object that is superior to all other objects in the hierarchy. All other objects are descendents of the root object.

Subtree

All of the descendents of a selected parent.

Branch

A path through the hierarchy from a parent to a single descendent.

Leaf

A child object that has no children of its own. The lowest object in a branch.

Link

The invisible connection between a parent and its child. The link is a conduit for transmitting position, rotation, and scale information from parent to child.

Pivot

Defines the local center and coordinate system for each object. You can think of links as connecting the pivot of a child object to the pivot of its parent.