A pyllora was a title used by Vulcans when initiating a mind meld with a relative. The pyllora acted as a guide or a counselor within a memory experienced by a Vulcan, to assist the subject from repressing the memory.
In 2373, Lieutenant Tuvok asked his close friend and commanding officer, Captain Kathryn Janeway to act as his pyllora, as Tuvok's family members were on the other side of the galaxy due to the USS Voyager being stranded in the Delta Quadrant. Their task was to get to the bottom of a supposed traumatic memory Tuvok had about a young girl falling from a precipice. However, Tuvok's mind meld with Janeway instead took both of them to his memories of his first posting in Starfleet; the USS Excelsior, commanded by Captain Hikaru Sulu and the Excelsior's battle with Kang near Qo'noS in the Azure Nebula. (VOY: "Flashback")