Entrepreneurship is the pursuit of opportunity without regard to resources currently controlled.

I love that definition. “Entrepreneur” is an overused term, but there really is nothing else that encapsulates the idea. And I’ve found no definition like the one above that so succinctly explains what it means to be an entrepreneur.

Since starting my own business almost one year ago, I find myself thinking differently. I think ahead—far ahead—and rarely think about the past. I think about my success in terms of not how many clients I have, or how much money I’m making, but what portion of the possible I’m turning into something real. And what is and isn’t possible means something very different than it did, for me, just a few years ago.

That’s what entrepreneurship is about, and that’s what this definition explains so well. What is possible and impossible is not an objective, set-in-stone list of things. Possible is an relative term. Entrepreneurs simply understand this more than do most other people.

I like to use the following illustration: Go back to an ancient Roman city. Survey the town members on the question: “Is it possible to talk with someone on the other side of the world?” I’ll bet the answer is a resounding no. But today, of course, we do this daily with our phones. It is possible, and it was never actually impossible. It was just beyond the limits of ancient people’s imagination. And probably those who did imagine such an ability, or such a technology, were considered insane.

Thank God for entrepreneurs, like Alexander Graham Bell (inventor of the telephone), who saw nothing impossible about their ambitions to change the world—who pursued an opportunity without regard to resources currently controlled or available.

For those who care, that definition was coined by Harvard Business School’s Howard Stevenson.