argument
A text that takes a position on a debatable issue and supports it with reasons and evidence.
claim
The writer's position, stated clearly. In an essay it is the thesis.
counterclaim
An opposing position that a reasonable person might hold.
rebuttal
The writer's response to a counterclaim, explaining why the claim is still stronger.
concede
To admit that part of the other side's point is true.
evidence
Facts, statistics, examples, expert statements or experiences that support a reason.
appeal
A way of convincing: to logic (reasons and evidence), to trust (credibility) or to emotion (feelings).
fallacy
A mistake in reasoning that makes an argument weaker, even if it sounds convincing.