Ecommerce or E-Commerce? Which is best for SEO?

I am going to start by saying that I am biased. It seams that dictionaries, spell checks, and auto-correct all agree that e-commerce is the way it is written. However, all throughout Google's documentation, they call it Ecommerce. So, which do we go with? Do we conform to the traditional rules that dictionaries are always correct, or do we go with the giant search engine who determines the fate of a website based on it's content? 

• UX
• Technical
• Marketing
• Ecommerce