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

tortoise \tor"toise\, n. oe. tortuce, fr. of. tortis crooked,
   fr. l. tortus twisted, crooked, contorted, p. p. of torquere,
   tortum, to wind; cf. f. tortue tortoise, ll. tortuca,
   tartuca, pr. tortesa crookedness, tortis crooked. so called
   in allusion to its crooked feet. see torture.
   1. zool. any one of numerous species of reptiles of the
      order testudinata.
      1913 webster

   note: the term is applied especially to the land and
         fresh-water species, while the marine species are
         generally called turtles, but the terms tortoise and
         turtle are used synonymously by many writers. see
         testudinata, terrapin, and turtle.
         1913 webster

   2. rom. antiq. same as testudo, 2.
      1913 webster

   box tortoise, land tortoise, etc. see under box,
      land, etc.

   painted tortoise. zool. see painted turtle, under
      painted.

   soft-shell tortoise. zool. see trionyx.

   spotted tortoise. zool. a small american fresh-water
      tortoise chelopus guttatus or nanemys guttatus
      having a blackish carapace on which are scattered round
      yellow spots.

   tortoise beetle zool., any one of numerous species of
      small tortoise-shaped beetles. many of them have a
      brilliant metallic luster. the larvae feed upon the leaves
      of various plants, and protect themselves beneath a mass
      of dried excrement held over the back by means of the
      caudal spines. the golden tortoise beetle cassida
      aurichalcea is found on the morning-glory vine and
      allied plants.

   tortoise plant. bot. see elephant's foot, under
      elephant.

   tortoise shell, the substance of the shell or horny plates
      of several species of sea turtles, especially of the
      hawkbill turtle. it is used in inlaying and in the
      manufacture of various ornamental articles.

   tortoise-shell butterfly zool., any one of several
      species of handsomely colored butterflies of the genus
      aglais, as aglais milberti, and aglais urticae, both
      of which, in the larva state, feed upon nettles.

   tortoise-shell turtle zool., the hawkbill turtle. see
      hawkbill.
      1913 webster
see also:
torture testudinata terrapin turtle testudo box tortoise 
land tortoise box land painted tortoise painted turtle 
painted soft-shell tortoise trionyx spotted tortoise chelopus guttatus 
nanemys guttatus tortoise beetle cassida aurichalcea tortoise plant elephant's foot 
elephant tortoise shell tortoise-shell butterfly aglais aglais milberti 
aglais urticae tortoise-shell turtle hawkbill 

[2] : WordNet (r) 2.0

tortoiseshell turtle
     n : pugnacious tropical sea turtle with a hawk-like beak; source
         of food and the best tortoiseshell syn: hawksbill
         turtle, hawksbill, hawkbill, eretmochelys imbricata
see also:
hawksbill turtle hawksbill hawkbill eretmochelys imbricata 

Turtle >> T Words
Turtle, definition of term: Turtle
turtle_pag1.html

Turtle Grass >> T Words
Turtle Grass, definition of term: Turtle Grass
turtle+grass_pag1.html

Snapping Turtle >> S Words
Snapping Turtle, definition of term: Snapping Turtle
snapping+turtle_pag1.html

Sea Turtle >> S Words
Sea Turtle, definition of term: Sea Turtle
sea+turtle_pag1.html

Painted Turtle >> P Words
Painted Turtle, definition of term: Painted Turtle
painted+turtle_pag1.html

Box Turtle >> B Words
Box Turtle, definition of term: Box Turtle
box+turtle_pag1.html