adj. & n.
adj. 1 of or relating to the group of Indo-European languages including Russian, Polish, and Czech. 2 of or relating to the Slavs.
n. the Slavonic language-group. Old Church Slavonic the earliest written Slavonic language, surviving as a liturgical language in the Orthodox Church.
[ med.L S(c)lavonicus f. S(c)lavonia country of Slavs f. Sclavus SLAV ]