There are certain facts that, once someone points them out to you, make you wonder how you went your entire life without noticing. The answer was usually right there — in the word itself, in the design of the object, or in something you've looked at a thousand times without thinking about it. Here are 18 of them: 1. "Footage" literally means "amount measured in feet." Early 35mm film was measured and sold by the foot in cutting rooms, with 16 frames per foot. The word dates back to 1916, and it stuck even after film went digital. 2. "Podcast" is a combination of "iPod" and "broadcast." The term was coined in 2004 when most people listened to them on iPods. The name stuck even though most people now listen on their phones. 3.…