What's in an egg?

What are the design features of an egg? rails, outline, bottom contours, rockers? Seems like the local shops are calling anything with a round nose and tail an egg. Thanks guys.

Generally, under 8’ with a rounded 15 - 17 inch nose, rounded 14- 16 inch tail and having an eggy look, hence the name.

I used to think an egg was a board that was only SAT upon and never ridden! There’re beaks and feet of wet chickens cracking through a lot of boards at my break. That’s good for me though.