Hypodiastole is a textual mark developed in ancient Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 texts before the separation of words by space

Space (punctuation)

In writing, a space is a blank area devoid of content, serving to separate words, letters, numbers, and punctuation. Conventions for interword and intersentence spaces vary among languages, and in some cases the spacing rules are quite complex....

s was commonplace. It was used together with the hyphen

Hyphen

The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. The hyphen should not be confused with dashes , which are longer and have different uses, or with the minus sign which is also longer...

 (enotikon) to mark how the words should be read correctly. A hyphen was placed between words that should be read as one, while a hypodiastole was put between words that would have been otherwise incorrectly separated. Compare «ἐστὶ,νοῦς» ("it is a mind") to «ἐστὶν,οὖς» ("it is an ear"), or «ὅ,τι» ("whatever") to «ὅτι» ("that"). The symbol looks somewhat similar to the comma

Comma (punctuation)

The comma is a punctuation mark. It has the same shape as an apostrophe or single closing quotation mark in many typefaces, but it differs from them in being placed on the baseline of the text. Some typefaces render it as a small line, slightly curved or straight but inclined from the vertical, or...

 but has different function and has its own character in Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 ISO/IEC 10646

Universal Character Set

The Universal Character Set , defined by the International Standard ISO/IEC 10646, Information technology — Universal multiple-octet coded character set , is a standard set of characters upon which many character encodings are based...

standard (U+2E12) (⸒).