What does the Spanish word Ydem mean?

I am translating a few Spanish shipping inventories from around the late 1700s into English. The word "Ydem" keeps showing up and I have no clue what it means in English, let alone Spanish. I cannot find it in any Spanish dictionary. Could it be short hand for a longer word? Or perhaps it is a word no longer used in the Spanish language. Any clues at to what this word means or source I can go to in order to find its meaning or usage in the documents I am working with.|||...idem= similar or the same; it's used to indicate a list of items that are the same.


...the same form, the same thing, the same author,etc.





Edit. In English is also "ditto"|||Kind of reminds me of Ibidem, a Latin word used in English to mean "the same source cited above."





Hey, that's pretty much what I said. They're cognates.