底てい面めんTop 35000MeaningsNoun1. bottom; underside; base2. base (of a polyhedron)Kanji used底bottom面surfacePitch accentていめんていめんExamples1まん丸まるに見みえるあのお月つきさまはね、実じつは円えん錐すいの底てい面めんなんだよ。The moon looks so perfectly round. It's actually the base of a cone, you know.