U+1F90 "ᾐ" Greek Small Letter Eta with Psili and Ypogegrammeni Unicode Character

U+1F90 "ᾐ" Greek Small Letter Eta with Psili and Ypogegrammeni is a composite glyph used in polytonic Greek orthography, combining the vowel eta (η) with the psili (smooth breathing mark) and a subscript iota (ypogegrammeni), which indicates a long diphthong resulting from the historic presence of an iota sound. This character is primarily employed in ancient and liturgical Greek texts to denote a specific phonetic and grammatical context, often appearing in word forms such as the dative or subjunctive, and it represents a nuanced aspect of Greek writing that modern monotonic Greek has largely simplified.