Defn: Having a medium orbital index; having orbits neither broad nor narrow; between megaseme and microseme.

MESOSIDERITE
Mes`o*sid"er*ite, n. Etym: [Meso- + siderite.] (Min.)

Defn: See the Note under Meteorite.

MESOSPERM
Mes"o*sperm, n. Etym: [Meso- + Gr. mésosperme.] (Bot.)

Defn: A membrane of a seed. See Secundine.

MESOSTATE
Mes"o*state, n. Etym: [Meso- + Gr. (Physiol.)

Defn: A product of metabolic action.

Note: Every mesostate is either an anastate or katastate, according as it is formed by an anabolic or katabolic process. See Metabolism.

MESOSTERNAL
Mes`o*ster"nal, a. (Anat.)

Defn: Of or pertaining to the mesosternum.