Incidental as a legal qualifier: subordinate rights or risks linked to employment, property control, and tax consequences. The term 'incidental' denotes a subordinate relation to a principal matter. Black's Law Dictionary defines it as having a minor role. 'Incident to employment' describes risks connected with a worker's job duties, while 'incidents of ownership' identifies control rights over property-such as changing beneficiaries, borrowing, assigning, or cancelling a life insurance policy-that affect estate inclusion for tax purposes.