Printer's Mark

Printer’s mark (used as trademark by early printers since 15th century) of Hakob Meghapart - the publisher of Friday Book. Latin letters, namely D. I. Z. and A., abbreviation stands for:
D – Del servus (God’s servant)
I – Iacobos (Hakob)
Z – Zanni (Tsanyan)
A – Armenius (Armenian)