We divide clothes into five layers, of which there are 4 functional ones and one ornamental. (Functional) layering itself can help insulate you from the environment and each layer also has its own separate function.
This is not to say that the functional layers should be plain, or uninteresting and that ornamental items should or do not hold any function.
Ultimately the designer does what they so choose, but as a rule of thumb we suggest that form should not impede on function.
Main purpose: Temperature regulation and moisture wicking
Important properties:
Related clothing items:
The base layer is designed to wick moisture (sweat) away from the skin and transport it to the outer layers of clothing, where it can evaporate more easily. This helps keep the skin dry and comfortable, and prevents the build-up of moisture that can lead to chafing or skin irritation.
The base layer also helps regulate body temperature by insulating the body and trapping heat close to the skin.
In cold weather, the base layer can help prevent heat loss and keep the body warm.
In warm weather, the base layer allows air to circulate around the body.