Eszett

A ligature (ß) used in the German language. It formed from the combination of the Fraktur lowercase s and z, of which the closest symbol to the ligature was the beta, thus forming the wonderfull eszett. The symbol itself is pronounced like a hard 's'.

More relevant information can be found at ess-tsett, but Eszett is the actual name of this symbol. Don't think of calling it a beta.

There is also a phenomenal connect four player who also goes by the name "eszett", based off of this symbol. As tempting as it is, don't confuse the two.