Also, and I'm not sure if I remember that correctly, I think during "Mac OS X" times they said it is pronounced as "mac OS ten", because X is the roman numeral

Also, and I'm not sure if I remember that correctly, I think during "Mac OS X" times they said it is pronounced as "mac OS ten", because X is the roman numeral for 10. Wikipedia has references about it where Apple themselves even back then used either pronunciation, though. Also a reference that says while it stands for 10 it also references the X commonly found in many Unix things because of the Unix roots of Mac OS X.