A synthesis reaction or direct combination reaction is one of the most common types of chemical reactions. In a synthesis reaction two or more chemical species combine to form a more complex product.
A design review is a milestone within a product development process whereby a design is evaluated against its requirements in order to verify the outcomes of previous activities and identify issues before committing to-and if need to be re-prioritise-further work.
To design is to conceive, create, sketch out, or invent something. An architect might design a new apartment building, and an inventor might design a new smart phone. That's a broad definition, but then again, design is a broad field.