kermes oakEnglishOxford New American Dictionarykermes oak /ˈkermēz, , ˈkɛrmiz, ˈkerməs ōk, ˈkɛrməs oʊk/ ▸ noun a very small evergreen Mediterranean oak which sometimes remains as a shrub. It has prickly leaves and was formerly prized as a host plant for kermes insects. Quercus coccifera, family Fagaceae.