Make the grade is an idiomatic AmE expression meaning:
- Satisfy the requirements, qualify; also, succeed. For example, Angela hoped her work in the new school would make the grade, or Barbara certainly has made the grade as a trial lawyer.
According to The American Heritage Dictionary of Idioms, this expression uses grade in the sense of "accepted standard." [c. 1900].
The Indu offers an alternative meaning of grade:
- In American English, ‘grade’ is also used to refer to a gradient or a slope. In the context of the idiom, it refers to the steep incline a train has to climb. A train that makes the grade is one that is successful in climbing a steep incline or slope.
and a similar interpretation is given by The Dictionary of American Slang
- 1912+; perhaps from a train's ability to climb up the grade or slope of the track.
- Is there more solid evidence of what "grade" refers to? If the "train" story is true, I guess the expression was probably popular in train/railways related contexts, at least in its earliest usages. Is there any evidence in that respect?