Question

James uses the word more to mean "i want another cookie." in this case, more is a(n) _____.

Answer 1

This is more of a holophrase.
Holophrase is what we call the usage of a single word in order to express complex ideas and whole sentences. For example when a child says "cookie" that is and example of holophrase as she is asking for a cookie. Toddlers use this and pass through this stage quite early. It is important to note that holophrase is used without grammatical intent.