Why did they drop "Junior High" in favor of "Middle School"?

The school I teach at uses block scheduling, but we don’t alternate. A student has four classes each semester, instead of eight-ish year-long classes.

Rotating schedules are also a thing at some schools. Like, you’ll have English in A period, and math in B, and so on, but on Monday the schedule is ABCDEFG, and then on Tuesday it’s BCDEFGA, and Wednesday is CDEFGAB, and so on. The benefit is that, if a student is often late or doesn’t function well right before lunch or whatever, that burden is spread out over all of the classes. The drawback is that, with schedules changing every day, it’s harder to hire part-time teachers.

I went to Catholic school K-8 for elementary school, then a stand alone freshman high public school and on to a 10-12 public high school. The reason for the stand alone freshman high was that that was where they had room because the high school had become overcrowded. The school district had just built a 7-8 middle school and they moved the frosh into the former junior high.