Hypodiastole

The hypodiastole (Greek: ὑποδιαστολή, hypodiastolḗ, lit. "lower separation [mark]"), also known as a diastole,[1] was an interpunct developed in late classical and Byzantine Greek texts before the separation of words by spaces was commonplace. In the scriptio continua then used, a group of letters might have separate meanings as a single word or as a pair of words. The papyrological hyphen (enotikon) showed a group of letters should be read together as a single word, while the hypodiastole showed that they should be taken separately. Compare "ὅ,τι" ("whatever") to "ὅτι" ("...that...").[2]

Hypodiastole. Note the difference from comma.

The hypodiastole was similar in appearance to the Greek comma and was eventually entirely conflated with it: in Modern Greek, the term ypodiastolī́ (υποδιαστολή) refers to the comma in its role as a decimal point and words such as ό,τι are written with standard commas. A separate Unicode point—ISO/IEC 10646 standard (U+2E12) (⸒)—exists for the hypodiastole but is only intended for reproductions of its historical occurrence in Greek texts.[2]