EURIBOR stands for the Euro Inter Bank Offered Rate. It is the rate at which European banks borrow money from each other, over a set period.
The lenders easy2loan.com works with use the EURIBOR as the reference index for building their variable rate mortgage schemes. It is most common in Spain to use the 12 month EURIBOR. In addition to the relevant EURIBOR rate there will be the lender's own set interest rate margin over and above EURIBOR (which might be, for example, 1.5% over the index).
Last update for the 12 month EURIBOR: