- MesopotamiaA geographic region in southwest Asia, spanning from the rivers Euphrates and Tigris, located in modern Iraq, eastern Syria, and southeast Turkey; the site of one of the most ancient civilizations in the history of man.
- mesoIn between the "macro" and "micro" levels of sociological structures.
- mesonThe mesial plane dividing the body into similar right and left halves.
- mesicCharacterized by an intermediate degree of moisture, in between xeric (dry) and hydric (wet); somewhat moist.
- mesialPertaining to the midline of the body.
- meso-Middle or centre in location/position.
- mesocarpThe middle layer of the pericarp of a fruit. In many fruits such as drupes and tomatoes, the mesocarp is fleshy
- mesodiplosisThe repetition of terms within successive sentences
- mesogasterThe mesogastrium.
- mesolethomsonite
- mesologyThe study of the mutual interrelationships between organisms and their environment; branch of biology; former term for ecology.
- mesophloeumcortex
- mesostichAn acrostic that spells out a word or message with its middle letters.
- mesozeugmaA zeugma where the governing word occurs in the middle of the sentence and governs clauses on either side.
- omphalomesaraicSynonym of omphalomesenteric.