The Collaborative International Dictionary of English v.0.48:

Bachelor \Bach"e*lor\ (b[a^]ch"[-e]*l[~e]r), n. [OF. bacheler
   young man, F. bachelier (cf. Pr. bacalar, Sp. bachiller, Pg.
   bacharel, It. baccalare), LL. baccalarius the tenant of a
   kind of farm called baccalaria, a soldier not old or rich
   enough to lead his retainers into battle with a banner, a
   person of an inferior academical degree aspiring to a
   doctorate. In the latter sense, it was afterward changed to
   baccalaureus. See Baccalaureate, n.]
   1. A man of any age who has not been married.
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            As merry and mellow an old bachelor as ever followed
            a hound.                              --W. Irving.
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   2. An unmarried woman. [Obs.] --B. Jonson.
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   3. A person who has taken the first or lowest degree in the
      liberal arts, or in some branch of science, at a college
      or university; as, a bachelor of arts.
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   4. A knight who had no standard of his own, but fought under
      the standard of another in the field; often, a young
      knight.
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   5. In the companies of London tradesmen, one not yet admitted
      to wear the livery; a junior member. [Obs.]
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   6. (Zool.) A kind of bass, an edible fresh-water fish
      (Pomoxys annularis) of the southern United States.
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