rea•son (ˈri zən)
n.

1. a basis or cause, as for some belief, action, fact, or event.
2. a statement presented in justification or explanation of a belief or action.
3. the mental powers concerned with forming conclusions, judgments, or inferences.
4. sound judgment; good sense.
5. normal or sound powers of mind; sanity.
6. Logic. a premise of an argument.
7. Philos.
a. the faculty or power of acquiring intellectual knowledge, either by direct understanding of first principles or by argument.
b. the power of intelligent and dispassionate thought, or of conduct influenced by such thought.
v.i.
8. to think or argue in a logical manner.
9. to form conclusions, judgments, or inferences from facts or premises.
10. to urge reasons that should determine belief or action.
v.t.
11. to think through logically, as a problem (often fol. by out).
12. to conclude or infer.
13. to convince, persuade, etc., by reasoning.
14. to support with reasons.

logic (ˈlɒdʒɪk)
n
1. (Logic) the branch of philosophy concerned with analysing the patterns of reasoning by which a conclusion is properly drawn from a set of premises, without reference tomeaning or context. See also formal logic, deduction⁴, induction⁴
2. (Logic) any particular formal system in which are defined axioms and rules of inference. Compare formal system, formal language
3. the system and principles of reasoning used in a specific field of study
4. a particular method of argument or reasoning
5. force or effectiveness in argument or dispute
6. reasoned thought or argument, as distinguished from irrationality
7. the relationship and interdependence of a series of events, facts, etc
8. (Logic) chop logic to use excessively subtle or involved logic or argument

On many sites on the internet the difference between logic and reason is given as:
Reason is subject to personal opinion, whereas logic is an actual science that follows clearly defined rules and tests for critical thinking. (http:www.wisegeek.com/what-is-the-difference-between-logic-and-reason.htm)

Logic is defined as core principles. Logic uses reason.

More information gleaned from the information highway (aka “the misinformation highway”) claims that reason assumes that every cause has an effect and that every effect has just one cause. Logic, meanwhile, assumes that similar causes lead to similar effects. Reason is voluntary and transient, while logic is involuntary and eternal. (www.answers.com/Q/What-is –the-difference-between-logic-and-reason)