mandorla or vesica piscis (if they have the same radius)

About 1.22R^2, where R is the width (radius of each forming circle). The exact formula is at: http://mathworld.wolfram.com/VesicaPiscis.html

No, but it is a prolate spheroid.

Alternative answer:

An American football is not well described by a prolate spheroid, though that shape can describe a rugby ball. An American football is more accurately described as a vesica piscis that has been rotated about it's long axis.

"(Urinary) bladder" is an English equivalent of "vesica."

Vox Piscis was created in 1627.