The substantive part of the headword is an adjective in either masculine or feminine form, but the addition of the definite article shows that it depends here on a feminine name or noun.
It seems to be an incomplete entry, the ascription of which is not clear, and Adler nothing says about it. Amongst the common sources of the Suda the likeliest connection with a grammatical feminine (this lemma occurs in the Synagoge and Hesychius in masculine dependence) is Laurentianus 59.16 at folium 173v: γαμήλιος ὠδή “bridal song”, which seems to refer to the scholia to Homer, Iliad 18.498. So it could be an Ambrosian entry, but this should be corroborated by an examination of the manuscripts Ambrosianus B12 sup. and Atheniensis 1065. Meanwhile, other possibilities for the feminine noun are 'bed' (εὐνή , κοίτη ) and 'feast/sacrifice' (θυσία ); see LSJ s.v.