In medicine the term course generally takes one of two meanings, both reflecting the sense of "path that something or someone moves along...process or sequence or steps":

A patient may be said to be at the beginning, the middle or the end, or at a particular stage of the course of a disease or a treatment. A precursor is a sign or event that precedes the course or a particular stage in the course of a disease, for example chills often are precursors to fevers.