When you have a five year old, you start to realize just how many times you use sayings. Princess is always asking me what something I said means and I started to think about where these sayings that we commonly use originated. Thanks to google, my unscholarly research:
The saying "rule of thumb" comes from an old English law that states a man can't beat his wife with a stick any bigger than the diameter of his thumb! I use that saying all the time but I had no idea!
We sometimes say, "sleep tight!" (and my dad used to add, "don't let the bed bugs bite!") This saying came from Colonial America where the beds were not of the box spring variety that we enjoy today. The mattress laid on top of a web of ropes. There was a tool - an iron type of gadget that looked somewhat like an old clothes pin but larger - which was used to tighten the ropes when they became too slack. Thus, the expression "sleep tight."
I frequently tell my daughter that she got up on the "wrong side of the bed", which puzzles her because there is only one side to get out of, since the other is against the wall! This saying comes from an old superstition that claimed it was unlucky to put the left foot down on the floor first when getting out of bed.
If you are told you have a "frog in your throat", you may be grossed out to know that medieval doctors thought that the secretions of a frog would cure a cough, and they would place a frog in the mouth of the unfortunate patient. (ewwww!)
Other things I find myself saying are "it's raining cats and dogs!" or "for Pete's sake" (Is it St. Peter?) or also, "for Heaven's sake" which is more self-explanatory. "Heavens to Betsy" (again, who is Betsy?)
You can say that it's "straight from the horse's mouth" which comes from the fact that a horse's age is evidenced by their teeth, so it's no use lying about how old they are!
Sometimes "a little bird told me" something. This phrase comes from the Bible. In Ecclesiastes 10:20 the writer warns us not to curse the king or the rich even in private or a 'bird of the air' may report what you say.
When my kids have something fantastical to say, I kid them and say they're "pulling the wool over my eyes", which comes from the days of white wigs which resembled sheep's wool.
I have been known to say, "knock on wood", which is a Celtic superstition that believed spirits lived in trees. When in trouble, people knocked on the trees and asked for help.
Sometimes we "beat around the bush", which is not getting straight to the point. Hunters would beat a bush to flush out the birds which other people would then catch.
When we say, "the cat got your tongue" we don't even think about what this really means! This originated way back in history when it was common practice to cut out the tongue of criminal and feed it to the animals kept by the King. The cat would literally have your tongue if you were unable to speak! (ewwwww!)
"When pigs fly" obviously means never! Because, just when have you seen a pig fly lately?
One that I inherited from my dad is "it's better than a poke in the eye with a sharp stick!" which he would use anytime we didn't like something. I think just about anything is better than that. Needless to say, whenever we complained it was his standard reply.
Speaking of eyes, this sure was an eye-opening exercise for me! Now that I know the origin of some of these sayings, it is quite likely that I will think twice before saying it!
Here's my "two cents". "Don't take any wooden nickels!"