You may have heard these terms being bandied about by various reporters recently, saying that so and so is a "prohibitive frontrunner," or talking about how someone isn't the "presumptive nominee" yet. What the heck does that mean?

To receive the Democratic nomination, a candidate needs 2025 out of 4049 delegates, while to win the Republican nomination, a candidate needs 1191 out of 2380 delegates. When a candidate doesn't have that number of delegates yet, but has such a substantial lead that it's prohibitive to the chances of other candidates catching up, they are referred to as a "prohibitive frontrunner." A candidate is the "presumptive nominee" when they've accumulated enough delegates to win the nomination through the primary/caucus process, but the party convention hasn't taken place yet, so they aren't officially the nominee yet.