From WikiChip
microprocessor family

A microprocessor family or a CPU family (also microcontroller family) is a group of microprocessors, microcontrollers, or component chips that make up one, developed by a specific manufacturer that share the same general architecture and feature set. Within a specific family, chips may be further classified according to their model which may have different capabilities, clock speeds, and applications. Models may be further divided into stepping which are minor refinements and tweaks in order to correct and enhance the stability and reliability of the model.

While families is a good way of classifying chip according to architecture, historically, there has been more than a few instances where developers introduces significant architectural changes to the same family, such as XD, NX, and various SSE extensions in the case of Intel.

On occasion, a manufacturer may decide to group a number of smaller microprocessor families into a larger extended family which represents a large groups of chips that share a common theme and possibly root ISA.

See also