http://www.masterorganicchemistry.com/2012/04/27/polar-protic-polar-aprotic-nonpolar-all-about-solvents/

That is one term I didn't learn in Chem 101🙂

Here is the source article where I ran into that word:

http://phys.org/news/2015-05-mechanism-aprotic-sodium-air-batteries.html