Definite article, dative, feminine, singular. Here this article qualifies the following noun, ekklesia, 'church.' Notice that it is inflected to agree in case, gender and number (genitive, feminine, singular) with the next word. This form of the definite article appears again four words down the line.
Notice the small iota (ι)under the last letter; it is called the 'iota subscript' and is often found under the letters alpha (α at the end of the next word), eta (η as here), and omega (ω as at the end of the last word on this line) especially when one of these letters ends a word. It is a relic of a diphthong. It is not pronounced but must always be written.
Open Alberith Greek Wordbook on declension of the definite article ho
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