Wiktionary
a minus
n. (context education English) A grade lower than "A" and higher than "B plus".
Usage examples of "a minus".
Bradley, you'll see there's a minus sign in front of the number, and a dot over the last nine.
I admitted that on a scale of ten he scored a minus three with me.
The plus sign in equation XIV-2 on page 337 should be a minus sign if it is to be consistent with the previous equations-- Wait!
The plus sign in equation XIV-2 on page 337 should be a minus sign if it is to be consistent with the previous equations--”.
At that speed, each electron becomes matter in a minus state, with a destructive power utterly out of proportion to its 'size.