incidence

Merriam-Webster's Word of the Day for October 9, 2015 is: incidence • \IN-suh-dunss\  • noun 1 a : [angle of incidence](https://www.merriam-webster.com/dictionary/angle of incidence) b : the arrival of something (such as a projectile or a ray of light) at a surface 2 a : an act or the fact or manner of falling upon or affecting : occurrence b : rate of occurrence or influence Examples: The neighborhood boasts excellent schools and a low incidence of crime. "[Meditation] may also help people with insomnia and lower the incidence, duration, and severity of acute respiratory illnesses, such as influenza.…" — Alexia Severson, The Las Cruces (New Mexico) Sun-News, 4 Sept. 2015 Did you know? The words incident, incidence, and instance may seem similar (and, in fact, incident and incidence are closely related), but they are not used identically. In current use, incidence usually means "rate of occurrence" and is often qualified in some way ("a high incidence of diabetes"). Incident usually refers to a particular event, often something unusual or unpleasant ("many such incidents go unreported"). Instance suggests a particular occurrence that is offered as an example ("another instance of bureaucratic bumbling"); it can also be synonymous with case ("many instances in which the wrong form was submitted"). The plural incidences sometimes occurs in such contexts as "several recent incidences of crime," but this use is often criticized as incorrect. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.