A simple sentence consists of only one clause. A compound sentence consists of two or more independent clauses. A complex sentence has at least one independent clause plus at least one dependent clause. A set of words with no independent clause may be an incomplete sentence, also called a sentence fragment. A sentence consisting of at least one dependent clause and at least two independent clauses may be called a complex-compound sentence or compound-complex sentence.
This is a companion discussion topic for the original entry at http://grammarerror.com/tags/sentence