Is it ensure, insure, or assure?
1670s as the name of a mineral, oxide of manganese, from French manganèse (16c.), from Italian manganese, alteration or corruption of Medieval Latin magnesia (see magnesia). From 1783 in English as the name of an element.
manganese man·ga·nese (māng'gə-nēz', -nēs')
A brittle metallic element, having several allotropes. It is alloyed with steel to increase strength. Atomic number 25; atomic weight 54.9380; melting point 1,246°C; boiling point 2,061°C; specific gravity 7.21 to 7.44; valence 1, 2, 3, 4, 6, 7.
A grayish-white, hard, brittle metallic element that occurs in several different minerals and in nodules on the ocean floor. It is used to increase the hardness and strength of steel and other important alloys. Atomic number 25; atomic weight 54.9380; melting point 1,244°C; boiling point 1,962°C; specific gravity 7.21 to 7.44; valence 1, 2, 3, 4, 6, 7. See Periodic Table.