The Collaborative International Dictionary of English v.0.48:

bog \bog\ (b[o^]g), n. [Ir. & Gael. bog soft, tender, moist: cf.
   Ir. bogach bog, moor, marsh, Gael. bogan quagmire.]
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   1. A quagmire filled with decayed moss and other vegetable
      matter; wet spongy ground where a heavy body is apt to
      sink; a marsh; a morass.
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            Appalled with thoughts of bog, or caverned pit,
            Of treacherous earth, subsiding where they tread.
                                                  --R. Jago.
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   2. A little elevated spot or clump of earth, roots, and
      grass, in a marsh or swamp. [Local, U. S.]
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   Bog bean. See Buck bean.

   Bog bumper (bump, to make a loud noise), Bog blitter,
   Bog bluiter, Bog jumper, the bittern. [Prov.]

   Bog butter, a hydrocarbon of butterlike consistence found
      in the peat bogs of Ireland.

   Bog earth (Min.), a soil composed for the most part of
      silex and partially decomposed vegetable fiber. --P. Cyc.

   Bog moss. (Bot.) Same as Sphagnum.

   Bog myrtle (Bot.), the sweet gale.

   Bog ore. (Min.)
      (a) An ore of iron found in boggy or swampy land; a
          variety of brown iron ore, or limonite.
      (b) Bog manganese, the hydrated peroxide of manganese.

   Bog rush (Bot.), any rush growing in bogs; saw grass.

   Bog spavin. See under Spavin.
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