Definition of "ionization" [i•on•i•za•tion]

• The formation of or separation into ions by heat, electrical discharge, radiation, or chemical reaction. (noun)
• The state of being ionized. (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.

• "This process is called ionization, which is why it is named "ionizing radiation.""
• "His systematic measurements showed that a decrease in ionization did occur up to"
• "As I was able to observe no reduction in ionization during the eclipse I decided that, essentially, the sun could not be the source of cosmic rays, at least as far as undeflected rays were concerned."