macroscopic: adjective, Greek makros = large, and skopein = to examine; hence, large enough to be seen with the naked eye, e.g., pertaining to gross anatomy.
mediastinum: derivation doubtful, but possibly from Latin medius = middle, and stans = standing; hence, a median vertical partition, adjective - mediastinal.
medulla: Latin = marrow; applied to part of an organ deep to its cortex, and to the spinal cord and adjoining part of brain stem, which may have been thought to be the marrow of the vertebral column, adjective - medullary pertains to the medulla of an organ or medulla oblongata.
membrane: Latin membrana = a thin sheet; adjective - membranous.
meninges: plural of Greek meninx = a membrane; adjective - meningeal.
mesenchyme: Greek mesos = middle, and chymos = juice; the embryonic connective tissue of the mesoderm.
mesentery: Greek mesos = middle, and enteron = intestine; hence, the peritoneal fold which tethers the centrally situated small intestine; adjective - mesenteric.
mesial: adjective - medial, used in dental anatomy.
mesoderm: Greek mesos = middle, and derma = skin; the middle germ layer of the embryo.
mesosalpinx: Greek mesos = middle, and salpinx = tube; hence, the intermediate part of the broad ligament.
metacarpus: Greek meta = after, and karpus = wrist; adjective - metacarpal.
metaphysis: Greek meta = after, and physis = growth; hence, the end of the shaft of a bone alongside the epiphysial or growth cartilage; adjective - metaphysial.
metatarsus: Greek meta = after, and tarsos = ankle; hence, the bones beyond the tarsus, adjective - metatarsal.
metencephalon: Greek meta = beside, behind, or after, and enkephalos = brain; hence the parts of the hindbrain immediately caudal to the fore- and midbrain, namely the pons and cerebellum.