Iota adscript
From Textus Receptus
In Greek polytonic orthography, the iota adscript (Greek προσγεγραμμένη) is a iota written after a long vowel in a long diphthong, as opposed to below the vowel as a small vertical stroke (iota subscript; ὑπογεγραμμένη).
The iota subscript was created when the iota was reintroduced in the Byzantine period, to correct the loss of ι from copies of earlier manuscripts, but was placed below rather than beside the vowel to reflect the fact that it was not, by then, pronounced. This is still the most common convention today, although over the past few decades, many editors have preferred to reinstate the iota as an adscript. Others take a mixed approach, using the adscript for capitals, but the subscript for lower case letters.
