What does the phrase "on the merits" mean?

If you're following the news on Trump v Anderson - among other cases - you'll hear this phrase alot.

What does it mean?

- Click here for one explanation: 

The phrase “on the merits” refers to a case whose decision rests upon the law as it applied to the particular evidence and facts presented in the case. This is in opposition to cases whose decisions rest upon procedural grounds. The distinction between decisions that rest on the merits rather than on procedural grounds is important because a decision on the merits is considered final and is thus bound by res judicata. If a decision is bound by res judicata, the parties involved in the case may not later raise those same claims in a subsequent case. Instead, a party that disagrees with the decision must appeal the decision, file a motion for a new trial, or a file a motion to reconsider. Decisions that do not rest on the merits, however, are not bound by res judicata because the claims were not properly heard. Thus, these claims may be brought forth in a subsequent case, excluding dismissals due to a failure to state a claim.