Noun
eleventh grade (plural eleventh grades)
(US, education) The period in school that comes after tenth grade and before twelfth grade.
Those who don't remember the past are condemned to repeat the eleventh grade. James W. Loewen
I flip ahead in the textbook. There's an interesting chapter about acid rain. Nothing about sex. We aren't scheduled to learn about that until eleventh grade. Laurie Halse Anderson