Meaning: Repeatedly taking successive turns in the same order.
Example: Everyone in this family will take round robin turns putting out the trash, everyone that is except me.
Origin: "Round robin" originated in the British nautical tradition. Sailors wishing to mutiny would sign their names in a circle so the leader could not be identified.
Example: This bedroom doesn't even have enough room to swing a cat.
Origin: This colorful phrase evokes strange images of feline cruelty. In fact it has nothing to do with cats, but the real story is at least as cruel. The "cat" is a cat-of-nine-tails, a type of whip used to discipline sailors on old sailing ships.
The cat-of-nine-tails has one handle to which is attached nine thin strips of leather, each perhaps three feet long. The cat-of-nine-tails would be used to administer lashings that would sting and leave welts on the recipient.
The whippings would take place on the deck, because below deck there was not enough ceiling height to swing a cat-of-nine-tails.
Interestingly, the Disney cartoon character Mickey Mouse once gave a graphic illustration with some comic relief to this phrase. In the 1920's "Steamboat Willie" was release as Mickey Mouse's first cartoon. There is a scene in the cartoon in which Mickey is on a boat. He proceeds to pick up a cat and swing it around by the tail. Apparently this particular boat had enough room to swing a cat.
William Beveridge is the person attributed with coming up with this phrase, meaning to strain to remember or solve something, back in 1680. The rack was an instrument of torture on which peoples' bodies were stretched. Beveridge noted that at times people seem to be stretching their minds to get it to function as desired: "They rack their brains...they hazard their lives for it."
Nobody knows for sure where it came from. The Black Plague of the 1600s is the most widely accepted origin of the song, with good reason. Most scholars explain the song this way:
Ring around the rosy - rosy refers to the rose-colored rash people developed.
A pocket full of posies - posies were herbs used to sweeten the air from the smell of death.
Atchoo, atchoo - these were the original words to the song, having been traced as far back as the 1800's.
We all fall down - I don't think I need to explain this one, do I?
Now for the other side of the argument. There are some scholars who disagree with the Plague reference simply because there are a great deal of records detailing how the Plague started, how it spread, what the symptoms were, how it disappeared, how many people died, and the way that people lived. Yet it wasn't until the 1800's, almost two centuries after the Plague, that the first reference of the song appeared.