Which term describes the act of writing a will and the formal process surrounding that act?

The correct term for the act of writing a will and the formal process surrounding that act is probate. Probate refers to the legal process through which a deceased person's will is validated, and their estate is administered according to the wishes laid out in that will. This process involves proving the validity of the will, gathering the assets of the estate, paying any debts and taxes owed, and distributing the remaining assets to the beneficiaries as stipulated in the will.

While other terms like testamentary, estate planning, and will execution are related to wills, they refer to different aspects of the overall process. Testamentary relates to the instrument or provision of a will, estate planning encompasses the broader strategy of preparing for the management of an individual's assets and affairs after death, and will execution typically refers to the act of signing and witnessing the will itself. In contrast, probate specifically addresses the procedural aspects that follow the death of an individual and the formalities required for enforcing the will and administering the estate.