Steve Blank, a serial entrepreneur turned professor, offers a succinct and excellent answer to the commonly asked question, "What's a startup?"

Presented as a part of Sprikle Labs's "Now I Know" series, Blank frames his answer around his parent's entrepreneurial story of opening a grocery story and how a small business differs from a startup, or what he specifically calls a "scalable startup."

"Outside of technology clusters like Silicon Valley," Blank says, "the words entrepreneurship and startup mean small business." He continues, "Truly, (startups) do something different than small businesses even though we use the same words."

Blank tells how Chicago-based 37signals began as a small business, a web design firm, but later shifted to become a startup, making web applications like Basecamp, Highrise and Campfire. (The company has a timeline of this shift on its about page.)

"What I think we do (in startups)," Blank says, "is that founders wake up every morning saying, 'I don't just want to be self-employed, I want to take over the universe, I want to change the world, I want to do something important, this is the most exciting thing I could ever do.' "

Also worth noting, The Lean Launchpad, a free online class that Blank was scheduled to offer in February – we wrote about it on February 3 – has been postponed. Read more about the class on Blank's blog.

Hat tip to Geoff Wood.