D defs.my
Entry 4 senses Webster, 1913

Meso-

· Mes·o- · IPA
01 A combining form denoting in the middle, intermediate.
  1. 1.
    A combining form denoting in the middle, intermediate.
  2. 2.
    Denoting a type of hydrocarbons which are regarded as methenyl derivatives. Also used adjectively.(Chem.)
  3. 3.
    Optically inactive due to compensating optical activity at two or more asymmetric centers, often due to a plane of symmetry within the molecular structure; as, meso-tartaric acid.(Chem.)
  4. 4.
    Attached to a carbon atom located between two hereoatoms in a heterocyclic ring.