hy·​per·​thy·​me·​sia ˌhī-pər-ˌthī-ˈmē-zh(ē-)ə How to pronounce hyperthymesia (audio)
: the uncommon ability that allows a person to spontaneously recall with great accuracy and detail a vast number of personal events or experiences and their associated dates : highly superior autobiographical memory
People with hyperthymesia can recall almost every day of their lives in near perfect detail, as well as public events that are personally significant. Those affected describe their memories as uncontrollable associations, so when they come across a date, they "see" a vivid depiction of that day in their heads.Miriam Stoppard
Those equipped with hyperthymesia file away in their brains by default a detailed report on each day and can remember them in flawless detail, from news events, conversations they had to what they ate for breakfast. No matter how far removed, if prompted with a date, these individuals are able to pull the appropriate folder out of their mental file cabinet without hesitation.William J. Dowd

Word History


hyper- + -thymes- (probably extracted from Greek enthȳ́mēsis "consideration, reflection" or epithȳ́mēsis "longing, desire") + -ia entry 1; enthȳ́mēsis from enthȳméomai, enthȳ́mesthai "to ponder, consider, take to heart" (derivative of enthȳ́mios "taken to heart, weighing on the mind," from en- en- entry 2 + -thȳmios, derivative of thȳmos "spirit, mind, courage") + -sis -sis; epithȳ́mēsis from epithȳmeomai, epithȳ́mesthai "to set one's heart on, covet, desire" (derivative of epithȳmía "desire, yearning," from epi- epi- + thȳmós + -ia -ia entry 1) + -sis -sis — more at fume entry 1

Note: The term was apparently introduced by Elizabeth S. Parker, Larry Cahill, and James L. McGaugh in "A Case of Unusual Autobiographical Remembering," Neurocase, vol. 12 (2006), issue 1, pp. 35-49. The authors explain the coinage as follows: "We propose that AJ's form of autobiographical memory syndrome warrants its own definition and terminology. We suggest calling it the hyperthymestic syndrome, based on the Greek word 'thymesis' which means 'remembering,' and 'hyper' meaning 'more than normal.' The two defining features of hyperthymesia are: 1) the person spends an abnormally large amount of time thinking about his or her personal past, and 2) the person has an extraordinary capacity to recall specific events from their personal past." The authors do not give a source for their information about Greek, but in any case there seems to be no ancient Greek word thymesis. The etymology suggests several deverbal compounds that contain the element -thȳmēsis, and one must assume these are behind the coinage; however, though these words have to do with mental activity, they have no connection with memory, the Greek equivalent of which would be mnḗmē or mnēmosýnē. The word hyperthymestic, which the authors take as an adjectival derivative of hyperthymesia, is suggestive of Greek derivatives with mnē-, as hypomnēstikós "awakening the recollection, suggestive" and anamnēstikós "able to recall to mind readily" (compare amnēstía "forgetfulness," the source of amnesty entry 1). Compare, with Greek thȳmós as a base, dysthymia.

First Known Use

2006, in the meaning defined above

Time Traveler
The first known use of hyperthymesia was in 2006

Dictionary Entries Near hyperthymesia

Cite this Entry

“Hyperthymesia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hyperthymesia. Accessed 20 Apr. 2024.

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