The Collaborative International Dictionary of English v.0.48:

Hemlock \Hem"lock\, n. [OE. hemeluc, humloc, AS. hemlic,
   hymlic.]
   1. (Bot.) The name of several poisonous umbelliferous herbs
      having finely cut leaves and small white flowers, as the
      Cicuta maculata, Cicuta bulbifera, and Cicuta
      virosa, and the Conium maculatum. See Conium.
      [1913 Webster]

   Note: The potion of hemlock administered to Socrates is by
         some thought to have been a decoction of Cicuta
         virosa, or water hemlock, by others, of Conium
         maculatum.
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   2. (Bot.) An evergreen tree common in North America (Abies
      Canadensis or Tsuga Canadensis); hemlock spruce.
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            The murmuring pines and the hemlocks. --Longfellow.
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   3. The wood or timber of the hemlock tree.
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   Ground hemlock, or Dwarf hemlock. See under Ground.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Spruce \Spruce\ (spr[udd]s), n. [OE. Spruce or Pruse, Prussia,
   Prussian. So named because it was first known as a native of
   Prussia, or because its sprouts were used for making, spruce
   beer. Cf. Spruce beer, below, Spruce, a.]
   1. (Bot.) Any coniferous tree of the genus Picea, as the
      Norway spruce (Picea excelsa), and the white and black
      spruces of America (Picea alba and Picea nigra),
      besides several others in the far Northwest. See Picea.
      [1913 Webster]

   2. The wood or timber of the spruce tree.
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   3. Prussia leather; pruce. [Obs.]
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            Spruce, a sort of leather corruptly so called for
            Prussia leather.                      --E. Phillips.
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   Douglas spruce (Bot.), a valuable timber tree (Pseudotsuga
      Douglasii) of Northwestern America.

   Essence of spruce, a thick, dark-colored, bitterish, and
      acidulous liquid made by evaporating a decoction of the
      young branches of spruce.

   Hemlock spruce (Bot.), a graceful coniferous tree (Tsuga
      Canadensis) of North America. Its timber is valuable, and
      the bark is largely used in tanning leather.

   Spruce beer. [G. sprossenbier; sprosse sprout, shoot (akin
      to E. sprout, n.) + bier beer. The word was changed into
      spruce beer because the beer came from Prussia (OE.
      Spruce), or because it was made from the sprouts of the
      spruce. See Sprout, n., Beer, and cf. Spruce, n.] A
      kind of beer which is tinctured or flavored with spruce,
      either by means of the extract or by decoction.

   Spruce grouse. (Zool.) Same as Spruce partridge, below.


   Spruce leather. See Spruce, n., 3.

   Spruce partridge (Zool.), a handsome American grouse
      (Dendragapus Canadensis) found in Canada and the
      Northern United States; -- called also Canada grouse.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Tsuga canadensis
    n 1: common forest tree of the eastern United States and Canada;
         used especially for pulpwood [syn: eastern hemlock,
         Canadian hemlock, spruce pine, Tsuga canadensis]