When the body is lying face up, horizontally on one's back, this is called the supine position
Aside from the Latin, the most common term for lying on your back is supine.
Supine, in an anatomical sense, means lying on your back.
Supine isn't an animal, it's a medical/anatomical term for face up. If you lay on your back, then you're in a supine position. Face down is prone position.
proximal
ap supine
"supine" means lying down.
ap supine
Supine is the medical term meaning lying down facing up.
The difference between the Prone and Supine positions are that Supine is when you are laying on your back and prone is when you are lying flat on your stomach.
The word "supine" does not appear in Orson Scott Card's novel "Ender's Game." It is possible that you may have encountered the term in a different context or source.
semi supine or prone
Lying supine means lying on your back (supine is on your spine).