What does Sherlock call his Method of Loci memory technique?

Sherlock calls his Method of Loci memory technique a mind palace.

The phrase describes a visualization system in which information is organized inside an imagined physical space. Sherlock mentally enters this palace and retrieves details by moving through rooms, corridors or other locations populated with vivid images and associations. The television series uses the device as a dramatic representation of his exceptional memory and analytical process.

The underlying Method of Loci is much older than the show. It is traditionally associated with ancient Greek and Roman memory training, in which speakers imagined a familiar route and placed ideas at specific locations along it. “Mind palace” is the modern fictional character’s preferred expression, not the formal historical name of the technique.

Viewers may confuse the term with “memory palace,” which is a common general expression for the same mnemonic idea. In Sherlock, however, “mind palace” is the distinctive wording repeatedly associated with the detective, especially in episodes such as “The Hounds of Baskerville,” “The Empty Hearse” and “The Abominable Bride.”