ᴈ

(IPA): The letter was adopted into the IPA in 1921 as a turned epsilon ⟨ᴈ⟩. Sometime between the IPA chart published in 1957 and the 1989 Kiel Convention, it started to be rendered as a reversed epsilon ⟨ɜ⟩, its current form.

The Uralic Phonetic Alphabet makes regular use of 180°-rotation to denote a reduced form of a given sound.

ᴈ

1. (IPA, obsolete) An open-mid central unrounded vowel.
2. (superscript ⟨ᶟ⟩, IPA) [ᴈ]-coloring or a weak, fleeting, epenthetic or echo [ᴈ].
3. (UPA) a reduced ɛ vowel.
4. (superscript ⟨ᶟ⟩, UPA) an extremely short or fleeting ᴈ.

The superscript, U+1D4C, has the name of U+025C ᴈ but is defined in its Unicode properties instead as a superscript reversed epsilon ɜ, the same definition that U+1D9F ᶟ has. On the code chart is a note that the more appropriate equivalence would be to U+025C.