The term mole came from the word molecule and was coined by the German chemist Friedrich Ostwald in 1894. It is one of the most fundamental concepts in physical chemistry and usually introduced at the beginning of an upper secondary school chemistry syllabus. Despite the concept being ubiquitous in different topics of chemistry and applicable at every level of learning, it is often given a cursory treatment regarding its origins and merely presented to students as a definition. Monomole.com provides some relevant background to the development of the mole concept, including a few historically significant experiments that helped shape its definition over time, and explains other important physical chemistry concepts that are commonly encountered by students of chemistry.