noun

1. Minor items, not further defined. Incidental expense.

   “She's costing us a lot in incidentals.”

2. Something that is incidental.

adjective

1. Loosely associated; existing as a byproduct, tangent, or accident; being a likely consequence.

   “That character, though colorful, is incidental to the overall plot.”

2. Occurring by chance

3. (of radiation) Entering or approaching, prior to reflection (more frequently incident).

Synonyms: accidental, contingent, accidental, serendipitous