The Collaborative International Dictionary of English v.0.48:

Class \Class\ (kl[.a]s), n. [F. classe, fr. L. classis class,
   collection, fleet; akin to Gr. klh^sis a calling, kalei^n to
   call, E. claim, haul.]
   1. A group of individuals ranked together as possessing
      common characteristics; as, the different classes of
      society; the educated class; the lower classes.
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   2. A number of students in a school or college, of the same
      standing, or pursuing the same studies.
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   3. A comprehensive division of animate or inanimate objects,
      grouped together on account of their common
      characteristics, in any classification in natural science,
      and subdivided into orders, families, tribes, genera, etc.
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   4. A set; a kind or description, species or variety.
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            She had lost one class energies.      --Macaulay.
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   5. (Methodist Church) One of the sections into which a church
      or congregation is divided, and which is under the
      supervision of a class leader.
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   6. One session of formal instruction in which one or more
      teachers instruct a group on some subject. The class may
      be one of a course of classes, or a single special
      session.
      [PJC]

   7. A high degree of elegance, in dress or behavior; the
      quality of bearing oneself with dignity, grace, and social
      adeptness.
      [PJC]

   Class of a curve (Math.), the kind of a curve as expressed
      by the number of tangents that can be drawn from any point
      to the curve. A circle is of the second class.

   Class meeting (Methodist Church), a meeting of a class
      under the charge of a class leader, for counsel and
      relegious instruction.
      [1913 Webster]