Ryan made this guide to different common electronics connecters. He writes:
Online vendors, particularly sites like Jameco and Digikey, tend to be targeted at engineers who already know exactly what they’re looking for. If you don’t know the right search terms, finding the right part can be a bear. Since I made my start in electronics a few years ago, Octopart has made finding parts much easier, but you still have to know what you’re looking for! In hopes of helping people who’re building their first homebrew boards know what to look for, I’ve tried to compile a bit of what I’ve picked up.
I can never remember things like pin spacing and various other attributes of components, so this is a handy reference! – Link.