The Collaborative International Dictionary of English v.0.48:

Cultus \Cul"tus\ (k?l"t?s), n. sing. & pl.; E. pl. Cultuses
   (-?z). [L., cultivation, culture. See Cult.]
   Established or accepted religious rites or usages of worship;
   state of religious development. Cf. Cult, 2.
   [1913 Webster]