ep·i·blem \ˈepəˌblem\noun orep·i·ble·ma\ˌepəˈblēmə\ (-s) Etymology: New Latin epiblema, from Greek epiblēma covering, from epi- + blēma throw, coverlet, from ballein to throw — more at devil : the superficial layer of tissue replacing the true epidermis in most roots and in stems of submerged aquatics