Monolayer is a term that refers to a single layer of molecules or atoms. When it comes to synonyms, a few options include monomolecular, unilayer, and single-layer. The term monomolecular emphasizes that the layer is made up of individual molecules, while unilayer and single-layer highlight the fact that there is only one layer present. Other options include monoatomic, which suggests the layer is made up of single atoms, and monolitic, which is a less commonly used term that can refer to a thin layer of a single substance or material. Regardless of the specific synonym used, all of these terms describe a layer that is made up of a single component and is only one molecule or atom thick.