Through this video I stumbled on Tim Cooks areas of focus for running Apple - strategy, execution and people.
Sounds like a rather simple way to classify things but on thinking further, these really appear to be the all encompassing buckets into which you can put everything that happens inside a company.
Strategy - The whys and whats.
This would translate to a vision, roadmaps, go-to-marketing strategy, plans to stay solvent/make money. 
Execution - The when and how
Researching, building, maintaining, supporting, discontinuing and all that it takes to engines running.
People - The Who
Finding people, motivating them, matching their skills and your needs, shaping and supporting them, etc. 
It’s funny how terribly inter-twined these three aspects of a business are. Your who can determine your how and when and the other way around too!