The Verb refers to the Categorematic parts of speech:
it has lexical meaning and can take a definite syntactic position and serve some functions of a member of a sentence.
The Verb has its own Grammatical Meaning:
it expresses a dynamic sign which elapses in time, so it has the Grammatical Meaning of action:
* activity (e.g., We study and work);
* state (e.g., He feels happy);
* existence, a sign that an object or thing exists (e.g., A chair is a piece of furniture).
It has a propriety to show elapsed time of an action.