METACHROSIS
Met`a*chro"sis, n. Etym: [NL., from Gr. (Biol.)

Defn: The power og changing color at will by the expansion of special pigment cells, under nerve influence, as seen in many reptiles, fishes, etc. Cope.

METACINNABARITE
Met`a*cin"na*bar*ite, n. Etym: [Pref. meta- + cinnabar.] (Min.)

Defn: Sulphide of mercury in isometric form and black in color.

METACISM
Met"a*cism, n. Etym: [L. metacismus, Gr.

Defn: A defect in pronouncing the letter m, or a too frequent use of it.

METACROLEIN
Met`a*cro"le*in, n. Etym: [Pref. met- + acrolein.] (Chem.)

Defn: A polymeric modification of acrolein obtained by heating it with caustic potash. It is a crystalline substance having an aromatic odor.

METACROMION
Met`a*cro"mi*on, n. Etym: [NL.] (Anat.)

Defn: A process projecting backward and downward from the acromion of the scapula of some mammals.