Arrhenius base is a term often used in chemistry to describe a substance that releases hydroxide ions (OH-) in aqueous solutions. However, there are several synonyms used to represent this term in chemistry. Some of these synonyms include "alkali," "basic substance," and "proton acceptor." In addition to these, there are other terms such as "Brønsted-Lowry base," which refers to the ability of a substance to accept a proton, and "Lewis base," which describes a substance that donates an electron pair to form a covalent bond. All of these terms describe the same basic concept, and their usage may vary depending on the context and the type of chemical reaction under consideration.