Under cover

Cover \Cov"er\ (k?v"?r), n.
   1. Anything which is laid, set, or spread, upon, about, or
      over, another thing; an envelope; a lid; as, the cover of
      a book.
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   2. Anything which veils or conceals; a screen; disguise; a
      cloak. "Under cover of the night." -- Macaulay.
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            A handsome cover for imperfections.   --Collier.
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   3. Shelter; protection; as, the troops fought under cover of
      the batteries; the woods afforded a good cover.
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            Being compelled to lodge in the field . . . whilst
            his army was under cover, they might be forced to
            retire.                               --Clarendon.
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   4. (Hunting) The woods, underbrush, etc., which shelter and
      conceal game; covert; as, to beat a cover; to ride to
      cover.
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   5. That portion of a slate, tile, or shingle, which is hidden
      by the overlap of the course above. --Knight.
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   6. (Steam Engine) The lap of a slide valve.
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   7. [Cf. F. couvert.] A tablecloth, and the other table
      furniture; esp., the table furniture for the use of one
      person at a meal; as, covers were laid for fifty guests.
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   {To break cover}, to start from a covert or lair; -- said of
      game.

   {Under cover}, in an envelope, or within a letter; -- said of
      a written message.
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            Letters . . . dispatched under cover to her
            ladyship.                             --Thackeray.
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