Tom's explanation of the symbols he uses for Jim's coat of arms reflects his awareness that there are specific names given to specific parts of the seal and a standardized language used to describe those elements. However, Tom doesn't know what the actual terminology is and, as a result, can't use the correct terms for the parts of the coat of arms he has created. "Dexter" is the term used to refer to the left side of the shield, not along the top as Tom says. The term "nombril" refers to the center point of the shield, not a collection of "nombril points." He has the basic idea of what should be included in a coat of arms, but doesn't have the vocabulary to correctly name the elements.