The Collaborative International Dictionary of English v.0.48:

Groom \Groom\, n. [Cf. Scot. grome, groyme, grume, gome, guym,
   man, lover, OD. grom boy, youth; perh. the r is an insertion
   as in E. bridegroom, and the word is the same as AS. guma
   man. See Bridegroom.]
   1. A boy or young man; a waiter; a servant; especially, a man
      or boy who has charge of horses, or the stable. --Spenser.
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   2. One of several officers of the English royal household,
      chiefly in the lord chamberlain's department; as, the
      groom of the chamber; the groom of the stole.
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   3. A man recently married, or about to be married; a
      bridegroom. --Dryden.
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   Groom porter, formerly an officer in the English royal
      household, who attended to the furnishing of the king's
      lodgings and had certain privileges.
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