Topic = What is being discussed or written about. It is often a question to answer.
Claim = The answer to the question of the topic
Thesis statement = A statement of intention and purpose, expressing the central idea of an essay.
-- Adapted from Writing from Sources (8th edition) by Brenda Spatt
Let's define a little here:
A thesis statement will be a broad statement, worth defending, that defines the scope and limits of the essay.
1. The thesis will be a substantial generalization that can stand by itself. It should answer, not ask, a question.
Examples of topics, not theses:
2. The thesis will be broad enough and arguable enough to be worth defending. It will not be an obvious truth.
3. The thesis will define the scope and limits of the essay. The author should stay within the boundaries of the thesis and not digress into other topics.
Adapted from Writing from Sources (8th edition) by Brenda Spatt