You probably won’t be surprised to learn that exponent and proponent have a lot in common. While the two share visual similarities and closely related definitions, they also have a common ancestor: the Latin ponere, meaning “to put.” Exponent comes from exponere, meaning “to explain, expound, or set forth,” while proponent comes from proponere, meaning “to expose to view, bring to one’s attention, propose.” Today, proponent usually refers to someone who argues in favor of something. Exponent can also refer to someone who is an advocate, but it tends to refer especially to someone who stands out as a shining representative of something. In addition, it has kept its earlier meaning of “one who expounds,” as well as its mathematical symbol meaning.