Final answer:
The term that describes arrangements initially not written down but later formalized in a chart is 'Formal Arrangements.' This process signifies a transition from informality to documented clarity and organization.
Step-by-step explanation:
The term used to describe arrangements that were not written down initially but later became more formalized in a chart is Formal Arrangements. Initially, these arrangements might have been understood verbally or practiced informally among a group of people. Over time, to ensure clarity and consistency, these practices were documented, leading to the creation of formalized charts or documents that outline the specific processes, roles, or structures. This transition from an undocumented or informal arrangement to a documented format typically aims to improve organization and communication within an entity, be it a business, institution, or any other type of organization.