ß

The ess-tsett (ß) is a letter in German language orthography. It represents the ligature ss.

It originally derived from a Fraktur character representing the ligature of the long or medial s (ſ) with the short or terminal s (now the conventional s letterform.)

Until the standardization of German orthography (Neue Rechtschreibung) which came into effect in 1998, ß was used indiscriminately to represent the sound /s/. (A solitary s has the value /z/.)

In the Neue Rechtschreibung, ß is used only after a long vowel, and ss is used after a short one. For example, Fuß /fu:s/, with a long vowel, retains its ß, but Fluß /flυs/, with a short vowel, becomes Fluss. This is to accord with the orthography of other consonants, which are single after a long vowel and double after a short one; for example, egal with a long a and Ball with a short one.

This new usage of ß is now standard in Germany and Austria, but not in Switzerland, which routinely uses ss in all cases.

ß should not be confused with the lowercase Greek letter beta (β), which it resembles but to which it is unrelated.