How Did Weird Idioms Come About?
An idiom is a figure of speech that is used to mean something other than its literal meaning. "Riding shotgun" is an idiom for sitting in the passenger seat of a car. This phrase dates back to the early 1900s. In the Wild West, the person sitting beside the driver in coach would often carry a shotgun for protection. The idiom "barking up the wrong tree" came from the early 1800s when dogs were more commonly used for hunting. When a dog would identify prey that had run up a tree, the dog would bark upward toward it. When the prey jumped to a different tree, the dog would be left at the base of the original tree, confused, barking up to nothing.
from Mental Floss
Key Facts In This Video
An idiom is a figure of speech used to mean something other than its literal meaning. (0:02)
In the Wild West, the person sitting next to the driver would carry a shotgun, hence why sitting there is "riding shotgun." (1:34)
The phrase "close, but no cigar" was popularized in a 1935 screenplay about Annie Oakley. (5:14)