@malte
I didn't use one to define the other, I used one to explain why it is the same as the other Doing work is the same as inputting energy. Same concept, different words. Yes, they are used in different context to simplify the understanding, but in principle you can interchange them.

@malte
Yes and no. Work is the energy which "acts" in a process. It is the same concept, essentially.

@malte
Exactly. And if you think about it, it is actually the same, in a sense. Physics is about quantities you can measure.

@malte
Maybe I am a bit biased by German language here. When I started to discuss about physics in English, it was just particle physics, where nobody talks about work.

@malte
As I said it is used in slightly different context, still they describe the same physical quantity. Work is often used in the more dynamic context, when something is being moved, while energy is maybe more static. In university, we essentially never used work but always energy. Maybe the point is also that often "work" is used instead of "amount of work". So if you e. g. lift a body, you are doing work of e. g. 1 Joule, so you have used the energy of 1 Joule.

@malte
Work is another word for energy, used in a slightly different context. It is measured e. g. in Joule. A process is the sequence of changes.