What term is used to describe the start of a process or event?

The term that best describes the start of a process or event is "initiate." This word specifically conveys the action of beginning or starting something. It is frequently used in various contexts, including project management, scientific experiments, and procedural operations to indicate the point at which an action is taken to kick off a sequence of events.

While "commence" also implies a similar meaning, "initiate" tends to emphasize the action of starting with a sense of deliberate intention. Therefore, it is often the preferred term in contexts where the beginning of a process is being specifically highlighted. The other terms such as "conclude" and "develop" refer to ending a process and the progression of something over time respectively, which do not align with the concept of starting an event or process.