You are right. I used the term "enterprise software" only as a contrast to "consumer software". The "Fortune 5,000,000" is probably the best target market for a startup.
Why? Targeting large enterprises (what the company I work for does) is also an extremely difficult market, but for other reasons than the consumer market. Selling to large enterprises requires professionel and experienced sales people with very good industrie contacts. You also might run into the "small company problem", i.e. you don't sell because you look too small and you don't have enough customer references. Not much fun!
Why? Targeting large enterprises (what the company I work for does) is also an extremely difficult market, but for other reasons than the consumer market. Selling to large enterprises requires professionel and experienced sales people with very good industrie contacts. You also might run into the "small company problem", i.e. you don't sell because you look too small and you don't have enough customer references. Not much fun!