meso-, mes-, mesi-

(Greek: middle, intermediate; close to a center line; between)

mesocratic
A description of igneous rocks which are composed of a fairly equal proportion of light and dark minerals in nearly equal amounts.

It is intermediate in color between leucocratic (light-colored minerals) and melanocratic (dark-colored minerals).

mesocrystalline
Relating to crystalline rocks having crystals of a diameter intermediate between those of microcrystalline and macrocrystalline rocks.
mesocyclone
A region of low pressure circulating within a convective storm or a thunderstorm.
mesoderm
1. The third germ layer, lying between the ectoderm and the endoderm; which gives rise to the connective tissues, muscles, urogenital system, vascular system, and the epithelial lining of the coelom.

Any of three cellular layers, the ectoderm, endoderm, or mesoderm, into which most animal embryos differentiate and from which the organs and tissues of the body develop through further differentiation.

2. The middle of the three cell layers of the developing embryo.

It lies between the ectoderm and the endoderm where bone, connective tissue, muscle, blood, vascular and lymphatic tissue, and the pleurae (membrane that encloses each lung and lines the chest cavity) of the pericardium (membranous sac enclosing the heart) and peritoneum (membrane that lines the walls of the abdomen and the pelvis) are all derived from the mesoderm.

mesodermal
1. The third germ layer, lying between the ectoderm and endoderm which gives rise to the connective tissues, muscles, urogenital system, vascular system, and the epithelial lining of the coelom.
1. The germ layer (the third distinct layer of cells formed during an embryo's early stages of development) which forms many muscles, the circulatory and excretory systems, and the dermis, skeleton, and other supportive and connective tissues.
mesodont
A medium-sized tooth.
mesoduodenum
A fold of tissue which joins the duodenum (the first part of the small intestine, between the stomach and the jejunum or the middle part of the small intestine) to the wall of the abdomen of the fetus.
mesofauna (s) (noun), mesofaunas (pl)
The organism size category between tiny animals and large animals which includes such ground-dwelling creatures as mites, some insects, and their larvae, and springtails (any of numerous minute wingless primitive insects possessing a special abdominal appendage that act as springs to catapult them through the air and presents a nearly perpetual springing pattern; found in soil rich in organic debris or on the surface of snow or water).
mesogaster, mesogastrium
One of the two mesenteries (smooth serous membrane which lines the cavity of the abdomen) of the stomach.
mesogastric
1. Referring to or pertaining to the middle region of the abdomen, or of the stomach.
2. The middle area of the abdomen surrounding the navel.
mesogenous
Produced at or from the middle; such as, the spores of certain fungi.
mesogluteus
The middle gluteal muscle (three large muscles of each buttock), which abducts (draws away from the midline of the body or from an adjacent part or limb) and rotates the thigh medially or towards the middle.
mesognathism
Having the jaws slightly projecting; between prognathous (jaws projecting beyond the upper part of the face) and orthognathous (front of the head, or the skull, nearly perpendicular, not retreating backwards above the jaws).
mesognathous
1. Having medium, slightly protruding jaws.
2. Someone who has jaws that are of moderate size and project only slightly.
mesohaline
Pertaining to brackish water having a salinity between three and ten parts per thousand or sea water having a salinity between 30 and 34 parts per thousand.