This Web page defines "lean" as "small, tight code that won't waste your time or resources".
But lean as defined by Ries is not about code as much as it is about using validated learning to test market assumptions and only build what customers have verified that they want.
I'm not saying that lean startup methodology is a panacea for guaranteeing startup success; but it isn't about a style of coding, or minimizing how much you spend on your startup.