I have been looking into this term, Black Irish, lately, and it seems there are as many ideas about what it actually means as there are people thinking about it..
I don't know if there is any one definition that is *the right* one..
I have mixedblood Irish/African in at least one line of my family, but have heard the term Black Irish only once in regard to my family..so I have to conclude that in this instance, Black Irish means a mix of African and Irish..
There are a LOT of African/Irish or Irish/African people in this country stemming from one line of Irish slave owners alone...Taking into consideration how many Irish people and African people back in Colonial times probably married, and how many Irish people here were slave owners, the numbers of people who would be mixed African/Irish has to be pretty large..
What else could Black Irish ever have actually meant if not admixture between Irish and African??