Definer (noun)

A person or thing that defines, explains or clarifies something.

Origin:

The word "definer" is formed from the verb "define" which means to describe, explain, or make something clear and definite.

Examples:

1. The dictionary is a great definer of words.
2. The teacher acted as a definer for the class, helping them understand the concept.
3. The author of the book is considered an authority and definer on the subject.
4. The definer helped the company to create a clear and concise mission statement.
5. The definer tool helps to make the meaning of the word clear.