Extra Songs Added to iTunes

Hi all. Subject line pretty much sums it up. A neighbor friend and I were talking and somehow, Motion on the Ocean came up and so I decided to listen to Enya's song of the same name. So I connected my external drive to my Mac, and asked Siri to play it. Some other songs by Enya which I know I don't have came on in addition to the requested song. Anyone else ever had this happen before and if so, can I keep these other songs? I really like her music and would like to keep them if at all possible. Tia for anyone's help.