- a suffix found on nouns borrowed from Latin, especially derivatives of verbs (odium; tedium; colloquium; delirium), deverbal compounds with the initial element denoting the object of the verb (nasturtium), other types of compounds (equilibrium; millennium), and derivatives of personal nouns, often denoting the associated status or office (collegium; consortium; magisterium); -ium also occurs in scientific coinages on a Latin model, as in names of metallic elements (barium; titanium) and as a Latinization of Gk -ion (pericardium).
Origin of -ium
< New Latin, Latin, neuter suffix
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- indicating a metallic elementplatinum; barium
- (in chemistry) indicating groups forming positive ionsammonium chloride; hydroxonium ion
- indicating a biological structuresyncytium
New Latin, from Latin, from Greek -ion, diminutive suffix
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- Chemical element or group:californium.
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