What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Having, or of the nature of, a pseudocoelom; belonging to, characteristic of, or designating invertebrates of the group Pseudocoelomata.
An organism of the group Pseudocoelomata.
1940s; earliest use found in Libbie Hyman (1888–1969), zoologist. From pseudo- + coelomate, after scientific Latin Pseudocoelomata, subphylum or group name and (in later use) pseudocoelom.