A clause is a group of related words containing a subject and a verb A clause can be usefully distinguished from a phrase, which is a group of related words that does not contain a subject-verb relationship, such as "in the morning" or "running down the street" or "having grown used to this harassment." A review of the different kinds of phrasesmight be helpful.
Learning the various terms used to define and classify clauses can be a vocabulary lesson in itself. This digital handout categorizes clauses into independent and dependent clauses. This simply means that some clauses can stand by themselves, as separate sentences, and some can't. Another term for dependent clause is subordinate clause: this means that the clause is subordinate to another element (the independent clause) and depends on that other element for its meaning. The subordinate clause is created by a subordinating conjunction or dependent word.