Definition of "incidence" [in•ci•dence]

• The act or an instance of happening; occurrence: did not expect criticism and was surprised by its incidence. (noun)
• Extent or frequency of occurrence: a high incidence of malaria in the tropics. (noun)
• Physics The arrival of radiation or a projectile at a surface. (noun)
• Physics Angle of incidence. (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 any tax economist will tell you, who ultimately pays a tax (what they call the incidence of a tax) depends on the nature and circumstances of the tax."
• "The Total Federal Tax incidence is in the same table at the source."
• "Stroke incidence is a little more tricky, since strokes are multifactoral, but if clotting times are closer to normal, that's one less factor to worry about."