acoelomate
noun
acoe·lo·mate (ˌ)ā-ˈsē-lə-ˌmāt 
: an invertebrate lacking a coelom
especially : one belonging to the group comprising the flatworms and nemerteans and characterized by bilateral symmetry and a digestive cavity that is the only internal cavity
acoelomate adjective
Word History
Etymology
a- entry 2 + coelomate
First Known Use
circa 1889, in the meaning defined above
Medical Definition
acoelomate
noun
acoe·lo·mate (ˈ)ā-ˈsē-lə-ˌmāt
: an invertebrate lacking a coelom
especially : one belonging to the group comprising the flatworms and nemerteans (class Nemertea or Nemertinea) and characterized by bilateral symmetry and a digestive cavity that is the only internal cavity