1. [n]  the fusion of originally different inflected forms (resulting in a reduction in the use of inflections)
2. [n]  the union (or attempted union) of different systems (especially in religion or philosophy); "a syncretism of material and immaterial theories"

SYNCRETISM is a 10 letter word that starts with S.

1. \Syn"cre*tism\, n. (Philol.)
   The union or fusion into one of two or more originally
   different inflectional forms, as of two cases.
   
   

2. \Syn"cre*tism\, n. [Gr. ?, fr. ? to make two parties
   join against a third: cf. F. syncr['e]tisme.]
   Attempted union of principles or parties irreconcilably at
   variance with each other.
   
         He is plotting a carnal syncretism, and attempting the
         reconcilement of Christ and Belial.      --Baxter.
   
         Syncretism is opposed to eclecticism in philosophy.
                                                  --Krauth-Fleming.