Ten'chara
Established in the writers' second draft script of the  first season episode , Ten'chara was a Vulcan custom in which, once a year, betrothed spouses telepathically communicated with each other, briefly, while their families discussed the couple's future.

According to Commander , T'Pol had mentioned "Ten'chara" in a letter she had sent to her fiancé, Kos. Tucker was curious as to what the word meant, and when he asked T'Pol (while they were boxing) if it was "some kind of Vulcan mating custom," she explained what it really was, implying that Ten'chara was used to "begin the bonding process for marriage."

See also 
Mind meld
Telepathic mating bond
Vulcan mating rituals
Unused production material