As James Clackson points out the form meddíks that I cite at pp. 75 and 238 ( but not at 159. n. 5 where I cite the Latinized form meddix as at Liv. 23.35.13) is a nominative plural < *med(o)-dik-es with final syllable syncope of the old athematic nom. pl. ending *-es. The nom. sg. is meddíss (Cm 10 etc.) with assimilation from < *med(o)-dik-s.