The chart below is taken from one of the Gallup Corporation websites. It will give you a brief introduction to the 34 talents/themes from the StrengthsFinder Profile. The explanation is not a substitute for the complete descriptions in the book, "Now, Discover Your Strengths" but it is a start in understanding how talents/themes differ.
As defined in the book: a talent is defined as, "your naturally recurring patterns of thought, feeling, or behavior." That is what the profile measures.