one of the stores in the Multi-Store Model of Memory which stores memories for a long period of time, the only factor affecting their duration is natural degradation of memories with age.

LONG-TERM MEMORY (LTM): "One store of the various memory models which encodes and stores items for a prolonged period of time, however, items in the LTM are typically more subject to decay than items in the STM."
Cite this page: N., Pam M.S., "LONG-TERM MEMORY (LTM)," in PsychologyDictionary.org, April 7, 2013, https://psychologydictionary.org/long-term-memory-ltm/ (accessed October 19, 2021).