For example: this article (http://www.techrepublic.com/article/glossary-startup-and-ven...), gives the definition for "preferred stock" (a random selection) as "stock that carries a fixed dividend that is to be paid out before dividends carried by common stock." As someone not in the startup business (and not knowing much about finance in general), this is not really helpful. I'm not sure what it means for a dividend to be fixed, nor is there a definition of "common stock" anywhere.
I realize this isn't really the right thread to ask, but these things come up all the time so it seems like there might be a respectable reference somewhere online.