(music) An equivalence class of all pitches that are octaves apart, and which would be labeled by an integer, not a traditional letter name.

(music) An interval measured by the distance between its two pitch classes ordered so they are as close as possible.

(US) All students who have graduated or will graduate from a school in a given year.

A planned event at which members of a past school class meet.

Of or pertaining to the working class; suggestive of the working class in manner of speaking, outlook, appearance or other qualities.

Of a standard that ranks among the best in the world.

(taxonomy) A collection of organisms that is given formal recognition at the rank of class with a taxonomic name, but which is known to be an artificial group rather than a natural one.

(education) A class, typically in a performing art such as music or drama, in which a teacher listens to and critiques the performance of individual students, one at a time, while the other students look on.

Alternative spelling of second-class

The second-lowest rank in the Boy Scouts of America, between tenderfoot and first class.