1. undercloak - Noun
2. undercloak - Verb
undercloak (plural undercloaks)
(construction) A fixed underlayer of tile or fibre cement on a roof, to support the mortar above.
undercloak (third-person singular simple present undercloaks, present participle undercloaking, simple past and past participle undercloaked)
(construction, transitive) To apply such an underlayer to.