- a combining form meaning “middle,” used in the formation of compound words: mesocephalic.
- middle or intermediatemesomorph
word-forming element meaning “middle, intermediate, halfway,” sometimes mes- before vowels, comb. form of Greek mesos “middle, in the middle; middling, moderate; between” (see medial (adj.)). pref.
- In the middle; middle:mesoderm.
- Characterizing a superimposable isomer:meso-2,3-dichlorobutane.