* designatio: This is probably the closest general equivalent, referring to the act of designating, planning, or appointing. It suggests a more formal or deliberate process.
* conformatio: This emphasizes the shaping or forming aspect of design.
* ratio: This translates to "reason" or "plan," and might be suitable if referring to the underlying rationale or scheme of a design.
* structura: This refers to the structure or arrangement, and works well if the focus is on the organization of the design.
* forma: This means "shape" or "form," and is appropriate if the visual aspect is primary.
To choose the best translation, you need to specify what kind of design you're talking about. For example:
* The design of a building: `designatio aedificii` or `structura aedificii`
* The design of an experiment: `designatio experimenti` or `ratio experimenti`
* The design of a logo: `forma emblematis` or `conformatio emblematis`
Therefore, there's no single "right" answer. The best Latin word will depend on the context.