A figure of speech in which exaggeration is used for emphasis or effect, as in I could sleep for a year or This book weighs a ton. 1 A hyperbole is a deliberate exaggeration in which more is said than is literally meant, in order to add emphasis. When 10 of the Israelite spies reported on their exploration of the land of Canaan, they said, The cities are large and fortified to heaven (Deu. Deu. 1:28). Obviously they were not saying the walls of the Canaanite cities reached literally to heaven; they were simply stating that the walls were unusually high.2
1 American Heritage Online Dictionary, Ver. 3.0A, 3rd ed. (Houghton Mifflin, 1993), s.v. hyperbole.
2 Roy B. Zuck, Basic Bible Interpretation (Colorado Springs, CO: Cook Communications, 1991), 154.