Medical Definition of crustacea
1 capitalized : a large class of mostly aquatic arthropods that have a chitinous or calcareous and chitinous exoskeleton, a pair of often much modified appendages on each segment, and two pairs of antennae and that include the lobsters, shrimps, crabs, wood lice, water fleas, and barnacles
2: arthropods of the class Crustacea
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Dictionary: Definition of "crustacea"
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