phas·mid·ia \fazˈmidēə\noun plural Usage: capitalized Etymology: New Latin, from International Scientific Vocabulary phasmid + New Latin -ia in many classifications: a subclass of Nematoda comprising worms having phasmids, simple amphids like pores, usually deirids, and sensory organs that are typically papillose or, rarely, setose — compare aphasmidia • phas·mid·i·an\-dēən\noun-s