A type of computer memory from which items may be retrieved by matching some part of their content, rather than by specifying their ADDRESS (hence also called associative or content-addressable memory.) Associative memory is much slower than RAM, and is rarely encountered in mainstream computer designs.
For example, that serves as an identifying tag. Associative memory is used in multilevel memory systems, in which a small fast memory such as a cache may hold copies of some blocks of a larger memory for rapid access.
To retrieve a word from associative memory, a search key (or descriptor) must be presented that represents particular values of all or some of the bits of the word. This key is compared in parallel with the corresponding lock or tag bits of all stored words, and all words matching this key are signaled to be available.
Associative memory is expensive to implement as integrated circuitry.