Won-lost Record
Wins and losses, written as a record.
What it actually is. Wins first, losses second. The oldest shorthand in the game.
What a scout reads off it. For a club it is the point of the exercise and the only thing the standings care about. For a pitcher it is a team statistic wearing his name, because he cannot win a game his offense does not score in, which is why nobody has evaluated pitchers this way for a generation.
Where the lines are. A club at .600 is a serious contender, .500 is average by definition, and .400 is a rebuild. The gap between the best and worst records in a season is smaller than it feels, because even a bad club wins roughly six games in fifteen.
Batter's Eye: look up anything in baseball