n.
Function: noun
Date: 14th century
1 a : something kept hidden or unexplained : MYSTERY b : something kept from the knowledge of others or shared only confidentially with a few c : a method, formula, or process used in an art or operation and divulged only to those of one's own company or craft : TRADE SECRET d plural : the practices or knowledge making up the shared discipline or culture of an esoteric society
2 : a prayer traditionally said inaudibly by the celebrant just before the preface of the mass
3 : something taken to be a specific or key to a desired end <the secret of longevity>
– in secret : in a private place or manner