WordReference Random House Unabridged Dictionary of American English © 2026
mes•o•some
(mez′ə sōm′, mes′-, mē′zə-, -sə-),USA pronunciation n.
- Anatomy, Invertebratesthe anterior portion of the abdomen in arachnids.
- Microbiologya whorled structure extending inward from the cell membrane in Gram-positive bacteria and containing enzymes for cellular respiration.
- meso- + -some3 1955–60