What's "little" and what's "big?"

As you probably know, we have five "girls." The smallest - in terms of weight - is Emily, but for some reason I always think of Rosalita (aka "Piglet") as the smallest. Emily weighs around 45 pounds, Piglet about 50. So neither, in most people's worlds, are small dogs - right? Maybe it's just because they're the smallest dogs we've had in a while, and we've only ever had one that was smaller, Lucille, a party-colored cocker spaniel. But I digress a bit. Rosalita sleeps under the covers every night, either curled up at my stomach or all the way to our toes. Such a comfort. But, if somebody said to me, "Oh, my dog sleeps under the covers," my immediate vision would be a poodle, or a chiuaua. Or some combination of the two. But certainly not a 50-POUND DOG.