Blocks Palette

Default UI Menu: Tools/Palettes/Block

Ribbon UI Menu:

A block is a collection of objects combined into a single object. Blocks are useful for storing complex, common drawing objects that you will use more than once. Blocks are stored in the drawing's internal block library and a block reference, and not the actual object, is inserted into the drawing. When a block is edited, all instances of that block in the drawing are updated.