Groups

Two or more objects can be combined as a group. A group is treated as a single object for purposes of selecting and editing.
Each group contains its own drawing data. This means that making a copy of a group increases the size of your model. If you need to create several groups of numerous or complex objects, you may want to use blocks instead. Blocks are stored in a library, and each instance of the block refers to this external source, without significantly increasing the file size. See Blocks.
Because groups can contain groups and blocks, they can be complex hierarchical structures. The structure of a group can be seen in the Selection Info Palette (View / Selection Info), which can also be used to edit a group's contents. See Selection Info Palette.