@Beantin

I think that they are by some people intended to be two different aspects of controlling and allowing what goes into the machine instruction. Like this:

1. Prompt design is about writing prompts to get the desired output.

2. Prompt engineering is about the operational management of controlling what prompts are possible, i.e. restricting certain prompts to specific roles within a company in order to maintain data integrity and security, or controlling output length to manage computational costs.

Distinguishing between these two can be useful and set the right expectations, but I do see that prompt engineering is being used as a catch-all phrase. In that sense I would call prompt engineering the umbrella term for both the design/wording of prompts and the construction of rules for prompting.

But given that language is shaped by the people who use it we can only wait and see where these definitions end up. OpenAI themselves seem to use them interchangeably.