incident

(noun) a single distinct event.

(noun) a public disturbance. Example: "The police investigated an incident at the bus station."

(adj) falling or striking of light rays on something. Example: "Incident light."

(adj) (sometimes followed by `to') minor or casual or subordinate in significance or nature or occurring as a chance concomitant or consequence. Synonyms: incidental (vs. basic). Examples: "Incidental expenses." "The road will bring other incidental advantages." "Extra duties incidental to the job." "Labor problems incidental to a rapid expansion." "Confusion incidental to a quick change."