Verb
back butter (third-person singular simple present back butters, present participle back buttering, simple past and past participle back buttered)
Alternative form of back-butter
back-butter (third-person singular simple present back-butters, present participle back-buttering, simple past and past participle back-buttered)
(transitive, construction) To apply adhesive to the back of (a tile) before placing it on the substrate.
back-butter