| Noun | 1. | Tardigrada - in some classifications considered a separate phylum: microscopic arachnid-like invertebrates living in water or damp moss having 4 pairs of legs and instead of a mouth a pair of stylets or needlelike piercing organs connected with the pharynx Arthropoda, phylum Arthropoda - jointed-foot invertebrates: arachnids; crustaceans; insects; millipedes; centipedes tardigrade - an arthropod of the division Tardigrada class - (biology) a taxonomic group containing one or more orders |