I think you'll find that Aerian was not naming the order, rather stating what the order stands for. Vengeance comes in many forms and retribution is but one of them.
Retribution denotes a direct retaliation against another for crimes/sins against that person or their peers. Vengeance is an all-encompassing name that covers the entire realm of possible vengeance.
Please speak to me as the Senior Priest of the Order of Vengeance before you think to open your mouth with regards to my Patrons Order.
PS. no Finbar, it didn't get read, if it hasn't got paragraphs it gets skipped after the first sentence.
Written by my hand on the 26th of Midwinter, in the year 1072.