Things start getting more interesting and tangible when we start combining atoms together. Molecules are groups of atoms bonded together and are the smallest fundamental units of a compound. These molecules take on their own properties and serve as the backbone of our design systems.

For example, a form label, input or button aren’t too useful by themselves, but combine them together as a form and now they can actually do something together.

Building up to molecules from atoms encourages a “do one thing and do it well” mentality.

Molecules give us some building blocks to work with, and we can now combine them together to form organisms. Organisms are groups of molecules joined together to form a relatively complex, distinct section of an interface.

We’re starting to get increasingly concrete.

Organisms can consist of similar and/or different molecule types. For example, a masthead organism might consist of diverse components like a logo, primary navigation, search form, and list of social media channels. But a “product grid” organism might consist of the same molecule.

At the template stage, we break our chemistry analogy to get into language that makes more sense to our clients and our final output. Templates consist mostly of groups of organisms stitched together to form pages. It’s here where we start to see the design coming together and start seeing things like layout in action.

Templates are very concrete and provide context to all these relatively abstract molecules and organisms. Templates are also where clients start seeing the final design in place.

Pages are specific instances of templates. Here, placeholder content is replaced with real representative content to give an accurate depiction of what a user will ultimately see.

Pages are the highest level of fidelity and because they’re the most tangible, it’s typically where most people in the process spend most of their time and what most reviews revolve around.