- (symbol): ss
- A letter of the Latin script.
- (pharmacy) Apothecary symbol for half.
- 1624, Philip Barrough [i.e., Philip Barrow], “Of Making Bolus”, in The Method of Physick, Contaning[sic] the Cavses, Signes, and Cvres of Inward Diseases in Mans Body, from the Head to the Foote. Whereunto is Added, The Forme and Rule of Making Remedies and Medicines, which Our Physitions Commonly Vse at this Day, with the Proportion, Quantity, and Names of Each Medicine, book VII (in English), 6th edition, London: Imprinted by Richard Field, dwelling in great Woodstreete, OCLC 79430651, page 397:
- Bolvs in Engliſh is called a morſell. It is a medicine laxatiue, in forme and faſhion it is meanely whole, and it is ſwallowed by little gobbets. […] ℞ Medulla Caſſiæ fiſtulæ [n]ewly drawne, ℥. j. or ʒ. x. the graines, that is, the kernels, of Barberies, ℈. ß and with Sugar roſet [sugar compounded with rose petals], make a bole.
- (phoneme): IPA(key): /s/
- (letter name): IPA(key): /ɛsˈtsɛt/ (Eszett, usual)
- (letter name): IPA(key): /ˈʃarfəs ˈɛs/ (scharfes S, less desirable because it also refers to the sound /s/ regardless of its spelling)
In alphabetic ordering, ß is equivalent to the string ss. For example, one would order: Maske, Maß, Masse, Maße, Massen, Maßen, Mast. The letter also alternates with ss in inflections and derivatives, e.g. lassen → past tense ließ, though such cases are now fairly rare.
The current rules for the choice between ß and ss were introduced in 1996. They follow the simple principle that ss is used after short vowels and ß otherwise (i.e. after long vowels and diphthongs). Hence Masse /ˈmasə/ is distinguished from Maße /ˈmaːsə/. The earlier rules were more complicated and less phonetic. They prescribed that ß was additionally used in the syllable coda regardless of vowel length. Thus küssen, but er küßt, and Faß, but Fässer (modern spelling küsst, Fass). The older spelling has become rare, but is still used by some older language users.
In Switzerland and Liechtenstein, the letter ß is not used at all. So Straße is spelt Strasse, and the above distinction between Maße and Masse is lost in favour of the latter. This use is also often seen in Luxembourg and occasionally in South Tyrol, but ß is standard in both of these areas. Moreover one encounters the same spelling in German books printed in antiqua script until the early 20th century, because an antiqua ß did not yet exist. A rarer alternative was to replace ß with sz.
It is standard to replace ß with SS in all caps: STRASSE. However, in 2017 a new uppercase ẞ was introduced, so it is now also correct to spell STRAẞE. The use of a lowercase ß (STRAßE) is sometimes seen, but is proscribed. In capitalizing a few words which would become ambiguous if ß were changed to SS, SZ may be used instead, hence MASZE (Maße) may be kept distinct from MASSE (Masse), BUSZE (Buße) from BUSSE (Busse).