The imposition of words. This describes the ways in which words can be used, determined by their reference. It goes that any categorematic word can be used at any time in one of three impositions, or ways:

Zero imposition: The word refers to itself reflexively simply as a phonetic or orthographic concept, such as in the sentence "Cow has three letters." where 'cow' clearly refers to itself as a notation, a written word, and not to an actual cow.

First imposition: The word refers to the reality which it represents. This is the ordinary usage, such as in "The cow is eating grass."

Second imposition: The word refers to itself both as a phonetic/orthographic construct and as a grammatical unit, such as in "Cow is a noun." 

Now there's the idea of the intention of terms.

First intention: The term refers to the reality which it represents. This is analogous to the first imposition of words. 

Second intention: The term refers to itself reflexively, such as in the sentence "'Cow' is the object of my thought." (the concept 'cow' or idea of 'cowness'; the essence which the species represents.)

Now, here is my problem. How can a term ever refer to the 'reality' which it represents? Concepts don't exist, not in the way individuals exist. I don't understand how a concept can refer to anything other than itself; that is, be used in anything but second intention. I've heard this distinction is very important, so much so that logic was called by Scholastics "the science of second intentions" as grammar is "the science of second impositions."