The OP is discussing the type of curve where it is predetermined that only 10 As will be given, and 15 Bs and 20 Cs and so on. It’s used, apparently, to weed out students, or in situations where the desired outcome is only a certain # of students with each grade, and so students are graded against each other (in other words, if 20 students score in the typical A range of say 92-100, only the top 10 of those grades (maybe those over 96) will get an A, the rest will get A- or B or whatever).
It’s NOT referring to the type of curve where everyone is curved up.