MESOSTERNUM
Mes`o*ster"num, n. Etym: [Meso- + sternum.]

1. (Anat.)

Defn: The middle portion, or body, of the sternum.

2. (Zoöl.)

Defn: The ventral piece of the middle segment of the thorax in insects.

MESOTARTARIC
Mes`o*tar*tar"ic, a. Etym: [Meso- + tartaric.] (Chem.)

Defn: Pertaining to, or designating, an acid called also inactive tartaric acid.

MESOTHECA
Mes`o*the"ca, n. Etym: [NL., fr. Gr. (Zoöl.)

Defn: The middle layer of the gonophore in the Hydrozoa.

MESOTHELIUM
Mes`o*the"li*um, n. Etym: [NL., fr. Gr. thelium.] (Biol.)