According to Dr. David Chard, “Vocabulary knowledge is as essential to learning mathematics as it is to learning how to read.” [Chard] It is entirely possible for a person to possess an extensive vocabulary but be so deficient in a particular area (mathematics, chemistry, economics, medicine) to be essentially illiterate in that area. That is
Scholars frequently organize definitions into five categories: Persuasive, Precising, Theoretical, Lexical, and Stipulative. The last two are of interest to the mathematics teacher and student. A common name for a lexical definition is an extracted definition because it is extracted from common actual usage. Extracted definitions have a truth value—they can be true or false.