A glossary of important and frequently used words in Islam is presented. An attempt is made to find definitions of the most commonly used Arabic words from the Holy Verses and Ahadith, which we find are often different from the generally agreed-upon and in-use definitions. It is important to note that most Arabic words start with ‘Al’ or ‘Ba’ or change when expressed in singular/plural and based on gender (masculine/feminine). Furthermore, they change based on their grammatical role in the sentence. Therefore, multiple forms of an Arabic term may also be listed.