Polka dots and a dot
Someone asked me what the difference is between "polka dots" and "dots." I didn't know, so I looked it up. There really isn't much explanation out there about it, except that polka dots got their name when polka music was popular.
Wikipedia says they're ancient (!) but they "first became common on clothing in the late nineteenth century in Britain." They were also popular, of course, in the U.S. at that time and thereafter. Actually, they're probably popular throughout the world, except in countries that forbid pretty and cute clothing.
So, polka dots are a pattern, as seen here on this cute boot, and a dot is just one of those small circles within the pattern.