Kolinahr
From Memory Alpha, the free Star Trek reference.
Kolinahr (pronounced ko-li-naar) is the Vulcan ritual by which all remaining vestigial emotions are purged and the discipline whereby this is maintained. After rigorous training in the kahs-wan during childhood, a mature Vulcan is prepared to make this final journey to pure logic, the duration of which can vary from two to six years (or longer).
T'Klass was one of the first kolinahr masters and knew Surak. His mummified remains are kept in the catacombs of the T'Karath Sanctuary, but are not marked. (ENT: "Awakening")
Spock began the process of the kolinahr ritual after retiring from Starfleet circa 2270. By the end of his 2270s stay on Vulcan, Spock had completed all but the final ritual of the kolinahr, but refused to complete the ritual after receiving powerful telepathic signals from space (which were actually from V'Ger) and experiencing strong emotions as a result. (Star Trek: The Motion Picture)
Tuvok entered the pon farr during his sixth year of the ritual, and thus he left prematurely and married his betrothed wife.
When Asil, daughter of Tuvok and T'Pel, attained kolinahr, her father's friend Kathryn Janeway was present. (VOY: "Fury")
