For most of us, "sunglasses" are just "sunglasses." Whether or not they are "polarized" only tells us whether they are more expensive or less expensive. ("Polarized" is more expensive.)
But, when you buy polarized sunglasses, you are buying science. If you already have a pair of polarized sunglasses, you can do an interesting science experiment with them.
Most cell phone screens are also polarized. So, if you hold the cell phone in your right hand with the screen illuminated, and hold the polarized sunglasses in your left hand over the screen, looking through a polarized sunglasses lens at the screen, and rotate the lens clockwise or counterclockwise as you look through it, you will see the cell phone screen begin to vanish!
Next, find a calculator in the house with one of those LCD readouts -- one of those gold/beige/gray-colored screens with the not-very-easy-to-see black numbers composed of pieces of the number "8." After turning on the LCD screen, rotate the sunglasses over that. It vanishes!
Finally, if you have a flat-screen computer screen, rotate your polarized sunglasses in front of that.
It, too, vanishes.