[1] : The Collaborative International Dictionary of English v.0.48

thistle \this"tle\, n. oe. thistil, as. thornistel; akin to
   d.  g. distel, ohg. distila, distil, icel. thornistill,
   sw. tistel, dan. tidsel; of uncertain origin. bot.
   any one of several prickly composite plants, especially those
   of the genera cnicus, craduus, and onopordon. the name
   is often also applied to other prickly plants.
   1913 webster

   blessed thistle, carduus benedictus, so named because it
      was formerly considered an antidote to the bite of
      venomous creatures.

   bull thistle, cnicus lanceolatus, the common large
      thistle of neglected pastures.

   canada thistle, cnicus arvensis, a native of europe, but
      introduced into the united states from canada.

   cotton thistle, onopordon acanthium.

   fuller's thistle, the teasel.

   globe thistle, melon thistle, etc. see under globe,
      melon, etc.

   pine thistle, atractylis gummifera, a native of the
      mediterranean region. a vicid gum resin flows from the
      involucre.

   scotch thistle, either the cotton thistle, or the musk
      thistle, or the spear thistle; -- all used national
      emblems of scotland.

   sow thistle, sonchus oleraceus.

   spear thistle. same as bull thistle.

   star thistle, a species of centaurea. see centaurea.

   torch thistle, a candelabra-shaped plant of the genus
      cereus. see cereus.

   yellow thistle, cincus horridulus.
      1913 webster

   thistle bird zool., the american goldfinch, or
      yellow-bird spinus tristis; -- so called on account of
      its feeding on the seeds of thistles. see illust. under
      goldfinch.

   thistle butterfly zool., a handsomely colored american
      butterfly vanessa cardui whose larva feeds upon
      thistles; -- called also painted lady.

   thistle cock zool., the corn bunting emberiza
      militaria. prov. eng.

   thistle crown, a gold coin of england of the reign of james
      i., worth four shillings.

   thistle finch zool., the goldfinch; -- so called from its
      fondness for thistle seeds. prov. eng.

   thistle funnel, a funnel having a bulging body and flaring
      mouth.
      1913 webster
see also:
cnicus craduus onopordon blessed thistle carduus benedictus bull thistle 
cnicus lanceolatus canada thistle cnicus arvensis cotton thistle onopordon acanthium 
fuller's thistle globe thistle melon thistle globe melon 
pine thistle atractylis gummifera scotch thistle sow thistle sonchus oleraceus 
spear thistle star thistle centaurea torch thistle cereus 
yellow thistle cincus horridulus thistle bird spinus tristis goldfinch 
thistle butterfly vanessa cardui painted lady thistle cock emberiza militaria 
thistle crown thistle finch thistle funnel 

[2] : The Collaborative International Dictionary of English v.0.48

cotton \cot"ton\ ko^t"t'n, n. f. coton, sp. algodon the
   cotton plant and its wool, coton printed cotton, cloth, fr.
   ar. qutun, alqutun, cotton wool. cf. acton, hacqueton.
   1. a soft, downy substance, resembling fine wool, consisting
      of the unicellular twisted hairs which grow on the seeds
      of the cotton plant. long-staple cotton has a fiber
      sometimes almost two inches long; short-staple, from two
      thirds of an inch to an inch and a half.
      1913 webster

   2. the cotton plant. see cotten plant, below.
      1913 webster

   3. cloth made of cotton.
      1913 webster

   note: cotton is used as an adjective before many nouns in a
         sense which commonly needs no explanation; as, cotton
         bagging; cotton cloth; cotton goods; cotton industry;
         cotton mill; cotton spinning; cotton tick.
         1913 webster

   cotton cambric. see cambric, n., 2.

   cotton flannel, the manufactures' name for a heavy cotton
      fabric, twilled, and with a long plush nap. in england it
      is called swan's-down cotton, or canton flannel.

   cotton gin, a machine to separate the seeds from cotton,
      invented by eli whitney.

   cotton grass bot., a genus of plants eriphorum of the
      sedge family, having delicate capillary bristles
      surrounding the fruit seedlike achenia, which elongate
      at maturity and resemble tufts of cotton.

   cotton mouse zool., a field mouse hesperomys
      gossypinus, injurious to cotton crops.

   cotton plant bot., a plant of the genus gossypium, of
      several species, all growing in warm climates, and bearing
      the cotton of commerce. the common species, originally
      asiatic, is gossypium herbaceum.

   cotton press, a building and machinery in which cotton
      bales are compressed into smaller bulk for shipment; a
      press for baling cotton.

   cotton rose bot., a genus of composite herbs filago,
      covered with a white substance resembling cotton.

   cotton scale zool., a species of bark louse pulvinaria
      innumerabilis, which does great damage to the cotton
      plant.

   cotton shrub. same as cotton plant.

   cotton stainer zool., a species of hemipterous insect
      dysdercus suturellus, which seriously damages growing
      cotton by staining it; -- called also redbug.

   cotton thistle bot., the scotch thistle. see under
      thistle.

   cotton velvet, velvet in which the warp and woof are both
      of cotton, and the pile is of silk; also, velvet made
      wholly of cotton.

   cotton waste, the refuse of cotton mills.

   cotton wool, cotton in its raw or woolly state.

   cotton worm zool., a lepidopterous insect aletia
      argillacea, which in the larval state does great damage
      to the cotton plant by eating the leaves. it also feeds on
      corn, etc., and hence is often called corn worm, and
      southern army worm.
      1913 webster
see also:
acton hacqueton cotten plant cotton cambric cambric cotton flannel 
swan's-down cotton canton flannel cotton gin cotton grass eriphorum 
cotton mouse hesperomys gossypinus cotton plant gossypium gossypium herbaceum 
cotton press cotton rose filago cotton scale pulvinaria innumerabilis 
cotton shrub cotton stainer dysdercus suturellus redbug cotton thistle 
thistle cotton velvet cotton waste cotton wool cotton worm 
aletia argillacea corn worm southern army worm 

[3] : WordNet (r) 2.0

cotton thistle
     n : biennial eurasian white hairy thistle having pale purple
         flowers; naturalized in north america syn: woolly
         thistle, scotch thistle, onopordum acanthium, onopordon
         acanthium
see also:
woolly thistle scotch thistle onopordum acanthium onopordon acanthium 

Cotton >> C Words
Cotton, definition of term: Cotton
cotton_pag1.html

Thistle >> T Words
Thistle, definition of term: Thistle
thistle_pag1.html

Cotton Wool >> C Words
Cotton Wool, definition of term: Cotton Wool
cotton+wool_pag1.html

Cotton Grass >> C Words
Cotton Grass, definition of term: Cotton Grass
cotton+grass_pag1.html

Cotton Gin >> C Words
Cotton Gin, definition of term: Cotton Gin
cotton+gin_pag1.html

Scotch Thistle >> S Words
Scotch Thistle, definition of term: Scotch Thistle
scotch+thistle_pag1.html