class 
(klăs)
(klăs)n.
1. A set, collection, group, or configuration containing members regarded as having certain attributes or traits in common; a kind or category.
2. A division based on quality, rank, or grade, as:
a. A grade of mail: a package sent third class.
b. A quality of accommodation on public transport: tourist class.
3.
a. A social stratum whose members share certain economic, social, or cultural characteristics: the lower-income classes.
b. Social rank or caste, especially high rank.
c. Informal Elegance of style, taste, and manner: an actor with class.
4.
a. A group of students who are taught together, usually at a regularly scheduled time and in the same subject.
b. The period during which such a group meets: had to stay after class.
c. The subject material taught to or studied by such a group: found the math class challenging.
d. A group of students or alumni who have the same year of graduation.
5. Biology A taxonomic category ranking below a phylum or division and above an order.
6. Statistics An interval in a frequency distribution.
7. Linguistics A group of words belonging to the same grammatical category that share a particular set of morphological properties, such as a set of inflections.
8. Mathematics A collection of sets whose members share a specified property.
tr.v. classed, class·ing, class·es
To arrange, group, or rate according to qualities or characteristics; assign to a class; classify.
[French classe, from Latin classis, class of citizens; see kelə-2 in the Appendix of Indo-European roots.]