Bifacial refers to something that has two faces or surfaces. The antonyms for bifacial are words that describe something that has only one face. Monofacial, unifacial, or single-face are all antonyms for bifacial. These words imply that the object or material has only one side that is intended for use or observation. For example, a sheet of paper is monofacial, as it has only one side that is suitable for writing, drawing, or printing. In contrast, a coin is bifacial as it has a design or image on both sides. Understanding the antonyms of bifacial can help to clarify the intended usage or application of materials or objects.