Set associative cache combines the ideas of direct mapped and fully associative cache is as follows

• An N-way set associative cache mapping is like direct mapped cache in that a memory reference maps to a particular location in cache.
• A memory reference maps to a set of several (N) cache blocks, similar to the way in which fully associative cache works unlike direct mapped cache.
• A memory reference can map only to the subset of cache slots instead of mapping anywhere in the entire cache.
• In set associative cache mapping, a memory reference is divided into three fields. Those are tag, set, and word.
• As with direct-mapped cache, the word field chooses the word within the cache block, and the tag field uniquely identifies the memory address.