matchup
A specific pairing of opponents being compared or competing.
A matchup is when two opponents face each other in a competition or contest. In sports, when the Lakers play the Celtics, that's a matchup. When two chess players sit down across from each other at a tournament, that's a matchup too.
The word emphasizes the specific pairing and how each side's abilities will test the other. Coaches study matchups carefully, thinking about how their team's abilities compare to their opponent's. A fast basketball team might have a good matchup against a slower one. A tall volleyball player creates a tough matchup for shorter opponents at the net.
People also use matchup to talk about comparisons that aren't actual competitions. You might hear someone discuss the matchup between two video game characters, comparing their powers and abilities. Friends might debate the matchup between a lion and a bear (even though they'd never actually fight).
When you're preparing for any kind of competition, whether it's a spelling bee, a soccer game, or a debate, understanding the matchup helps you know what to expect and how to prepare.