DOP usually means date of pregnancy, basically when the pregnancy is dated from. Sometimes people confuse it with EDD which is the delivery date. Best to ask your doctor what exactly they wrote on your report so theres no mix up.
I saw DOP on my reports too and got confused. It generally refers to date of pregnancy or conception based dating. Your scan report and doctor will clarify the exact weeks though.
These abbreviations vary by clinic honestly. DOP often means date of pregnancy but its safest to ask the doctor who wrote it. Dont assume from online definitions for your own report.