crustacean(n = noun.animal) - any mainly aquatic arthropod usually having a segmented body and chitinous exoskeleton;
is a kind of arthropod
has parts: green gland, chela, claw, nipper, pincer
is a member of class crustacea, crustacea
has particulars: malacostracan crustacean, decapod, decapod crustacean, brachyuran, stomatopod, stomatopod crustacean, branchiopod, branchiopod crustacean, branchiopodan, copepod, copepod crustacean, mussel shrimp, ostracod, seed shrimp, barnacle, cirriped, cirripede

   crustacean(a = adj.pert) crustaceous - of or belonging to the class Crustacea;

   Of or pertaining to the Crustacea; crustaceous. [1913 Webster]

crustacean, n. & adj.
--n. any arthropod of the class Crustacea, having a hard shell and usu. aquatic, e.g. the crab, lobster, and shrimp.
--adj. of or relating to crustaceans.

Derivative:
crustaceology n. crustaceous adj.

Etymology:
mod.L crustaceus f. crusta: see CRUST

N  animal, animal kingdom, fauna, brute creation, beast, brute, creature, critter, wight, created being, creeping thing, living thing, dumb animal, dumb creature, zoophyte, mammal, bird, reptile, amphibian, fish, crustacean, shellfish, mollusk, worm, insect, arthropod, microbe, microbe, animalcule, alligator, crocodile, saurian, dinosaur (extinct), snake, serpent, viper, eft, asp, aspick, frog, toad, trout, bass, tuna, muskelunge, sailfish, sardine, mackerel, ant, mosquito, bee, honeybee, tardigrade, spider, biped, quadruped, webfoot, flocks and herds, live stock, domestic animals, wild animals, game, ferae naturae, beasts of the field, fowls of the air, denizens of the sea, black game, black grouse, blackcock, duck, grouse, plover, rail, snipe, horse, cattle, kine, ox, bull, bullock, cow, milch cow, calf, heifer, shorthorn, sheep, lamb, lambkin, ewe, ram, tup, pig, swine, boar, hog, sow, steer, stot, tag, teg, bison, buffalo, yak, zebu, dog, cat, dog, hound, pup, puppy, whelp, cur, mongrel, house dog, watch dog, sheep dog, shepherd's dog, sporting dog, fancy dog, lap dog, toy dog, bull dog, badger dog, mastiff, blood hound, grey hound, stag hound, deer hound, fox hound, otter hound, harrier, beagle, spaniel, pointer, setter, retriever, Newfoundland, water dog, water spaniel, pug, poodle, turnspit, terrier, fox terrier, Skye terrier, Dandie Dinmont, collie, feline, puss, pussy, grimalkin, gib cat, tom cat, fox, Reynard, vixen, stag, deer, hart, buck, doe, roe, caribou, coyote, elk, moose, musk ox, sambar, bird, poultry, fowl, cock, hen, chicken, chanticleer, partlet, rooster, dunghill cock, barn door fowl, feathered tribes, feathered songster, singing bird, dicky bird, canary, warbler, finch, aberdevine, cushat, cygnet, ringdove, siskin, swan, wood pigeon, vermin, varmint, pest, animal, zoological equine, bovine, vaccine, canine, feline, fishy, piscatory, piscatorial, molluscous, vermicular, gallinaceous, rasorial, solidungulate, soliped.

branchiopod crustacean, copepod crustacean, decapod crustacean, malacostracan crustacean, stomatopod crustacean