parasita

from The Century Dictionary.

• noun In zoology, parasites; parasitic animals: applied to several different groups whose members are characterized by their parasitism.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural An artificial group formerly made for parasitic insects, as lice, ticks, mites, etc.
• noun plural A division of copepod Crustacea, having a sucking mouth, as the lerneans. They are mostly parasites on fishes. Called also Siphonostomata.