PIE *ghredh「行く」、「段階」、「層」から。語源的にはingress「侵入」、aggressive「攻撃的」と同じ。後に一般化され、「等級」となった。
英語の語源
grade (n.)
1510s, "degree of measurement," from French grade "grade, degree" (16c.), from Latin gradus "step, pace, gait, walk; step on a ladder or stair;" figuratively "a step, stage, degree," from gradi (past participle gressus) "to walk, step, go," from PIE *ghredh- "to walk, go" (cognates: Lithuanian gridiju "to go, wander," Old Church Slavonic gredo "to come," Old Irish in-greinn "he pursues," and second element in congress, progress, etc.). Replaced Middle English gree "step, degree in a series," from Old French grei "step," from Latin gradus.
Meaning "inclination of a road or railroad" is from 1811. Meaning "class of things having the same quality or value" is from 1807; meaning "division of a school curriculum equivalent to one year" is from 1835; that of "letter-mark indicating assessment of a student's work" is from 1886 (earlier used of numerical grades). Grade A "top quality, fit for human consumption" (originally of milk) is from a U.S. system instituted in 1912. To figuratively make the grade "be successful" is from 1912; early examples do not make clear whether the literal grade in mind was one of elevation, quality, or scholarship.
grade (v.)
1650s, "to arrange in grades," from grade (n.). Meaning "to reduce (a road, etc.) to a level or degree of inclination" is from 1835. Meaning "assign a letter mark to" is from 1931. Related: Graded; grading.
例文
1. The boy first showed promise as an athlete in grade school.
この男の子は小学生の時に初めて選手になる潜在力を示した。
2.South Point College does not grade the students 'work.
南点学院は学生の宿題を採点しない。
3.It was actually used for enriching uranium to weapons- grade levels.
実際には、ウラン濃縮して武器を製造するために使用されています。
4.Simply sand them down with a fine grade of sandpaper.
細かいサンドペーパーで磨けばいい。
5.All parts are machined from top grade ，high tensile aluminium.