Definitions of sentence:

• noun:   a string of words satisfying the grammatical rules of a language

  Example: "He always spoke in grammatical sentences"

• noun:   the period of time a prisoner is imprisoned

  Example: "His sentence was 5 to 10 years"

• noun:   (criminal law) a final judgment of guilty in a criminal case and the punishment that is imposed
• verb:   pronounce a sentence on (somebody) in a court of law