#1.)  If you buy a TWO-BY-FOUR at the lumber store, it's not really two inches by four inches . . . it's one-and-a-half inches by three-and-a-half inches.

#2.)  PEANUTS aren't really nuts . . . they're legumes.  

#3.)  A KOALA BEAR isn't a bear . . . it's a marsupial, like a kangaroo.

#4.)  A STARFISH isn't a fish . . . it's something called an echinoderm.

#5.)  A PALM TREE isn't actually a tree.  It's a type of grass.

#6.)  And if you have SWOLLEN GLANDS, your glands aren't swollen . . . your lymph nodes are.

(NPR)