Occurring at the same time.
Of two signals, such that their corresponding significant instants are displaced by a constant interval of time.
Occurring by chance.
Entering or approaching, prior to reflection (more frequently incident).
Existing tangentially, being a byproduct, a tangent, or a likely consequence.
Loosely associated; of limited relevance except indirectly; only accidentally related.
Something that is incidental.
Minor items, not further defined. Incidental expense.