The Collaborative International Dictionary of English v.0.48:

Shinto \Shin"to\, Shintiism \Shin"ti*ism\, n. [Chin. shin god +
   tao way, doctrine.]
   One of the two great systems of religious belief in Japan.
   Its essence is ancestor worship, and sacrifice to dead
   heroes. [Written also Sintu, and Sintuism.]
   [1913 Webster]