Yours, Etc.: Origins and Uses of 8 Sign-Offs
1580s, from Middle French initiation or directly from Latin initiationem (nominative initiatio) "participation in secret rites," noun of action from past participle stem of initiare "originate, initiate," from initium (see initial).
initiation in·i·ti·a·tion (ĭ-nĭsh'ē-ā'shən)
The act or an instance of initiating.
The condition of being initiated.
The first stage of tumor induction by a carcinogen in which cells are altered so that they are likely to form a tumor upon subsequent exposure to a promoting agent.