Sentence is a group of words or a single word that expresses a complete thought, feeling, or
idea. It usually contains an explicit or implied subject and a predicate
containing a finite verb.
Compound is a word that is formed from two or more identifiable words, e.g. "blackbird," "notebook," "classroom,"
"cookbook," or "bullheaded," or, in some analyses, "mother-in-law" or "fire