The definition found on Wikipedia:
Ergonomics is "the scientific study of the relationship between man and his means, methods and working environments" and the application of this knowledge to the design of systems "that can be used with maximum comfort, safety and efficiency by the greatest number".
A simple definition of ergonomics:
Ergonomics consists of adapting work, tools and the environment to people (and not the other way around).
Which is ergonomic so is what is adapted .