Definition of "volcanism" []

• Volcanic force or activity. (noun)
• The phenomena associated with volcanic activity. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "As Italy is one of the most recently developed parts of the mainland and of the crust that has risen above the waters, it is subject to the phenomena that are due to that internal energy of the earth called volcanism, which is manifested in the various forms of volcanic activity, in earthquakes and in microseisms."
• "ET, the distribution of heatflow on earth is in the first place determined by the distribution of oceanic basaltic volcanism, which is in it’s turn determined by mid-oceanic ridges, which position is driven by viscous sic flow in the upper mantle."
• "Formed the idea of uniformitarianism stating current geologic processes, such as volcanism and erosion, have been at work throughout Earth's history."