Term generally applied to anybody descended of Irish heritage as well as Hispanic. (I.E., Mexican, Puerto Rican, Argentinian, etc.)
The Irish settled all over the Americas, not just North America, as is commonly believed. Those that settled, and mixed in with the Hispanic nations, are sometimes referred to as "Irican".
The term also applies to anybody, regardless of nationality, who has both Hispanic and Irish blood.
An Irican's liver is in far worse condition than other Irish folks, due to the fact that they drink whiskey in addition to tequila.