incidence

/IH1 N S AH0 D AH0 N S/
noun
  1. 1

    The act of something happening; occurrence.

  2. 2

    The extent or the relative frequency of something happening.

  3. 3

    The manner of falling; bearing or onus, as of a tax that falls unequally.

  4. 4

    The striking of radiation or a projectile upon a surface.

  5. 5

    A measure of the rate of new occurrence of a given medical condition in a population within a specified period of time.

  6. 6

    The falling of a point on a line, or a line on a plane.

Source: https://en.wiktionary.org/wiki/incidence