What ᪸ means
It tells you to open the vowel further.
Teuthonista is a system for writing detailed dialect pronunciation. In it, e᪸ marks an e more open or lower than plain e; ᪸ is stronger than ᪷, the single open mark. The exact vowel value depends on the transcription system and the letter it follows.
The mark also appears in Romance dialect transcription; it does not carry one guaranteed vowel value across the related German and Romance systems.
Where did ᪸ come from?
It developed within nineteenth-century dialect transcription.
Lepsius's notation for writing sounds dates to 1855. Ascoli published a related system for Romance dialects in 1873; Lenz's German system was developed by 1900. Teuchert revised that German tradition as Teuthonista in 1924–1925, a system for recording dialect pronunciation in detail.
The open-mark tradition also connects to Böhmer–Ascoli notation, a system for recording Romance dialects, and to the International Phonetic Alphabet (IPA). Romance dialect transcriptions also use the double mark.
Why does ᪸ look different in different places?
The font and the character it follows affect its display.
᪸ is meant to follow a base letter, as in e᪸. Fonts can position it differently; with no base, some editors show a dotted circle, while missing font support can produce a box or a floating mark.
Specialist phonetic notation for detailed dialect transcription; it belongs beside the vowel it describes.
By itself, ᪸ has no vowel to modify; it needs a base letter.
Don't confuse it with
1Combination ideas
1Questions people ask
1᪸ font support: why does it show as a box?
That is usually a font fallback. The mark needs a base letter; unsupported text may show a box or floating mark, while some editors show a dotted circle for a standalone mark. Check `e᪸` in a font that supports it.
How to type ᪸
᪸\1AB8Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.