Has the account that customers use to log into Apple services always been known as an Apple ID?

Has the account that customers use to log into Apple's various services always been known as an "Apple ID" - or was this originally known as a different name? As an example - when the iTunes Store originally launched, no reference is made as to the name of the account that customers used at the time to make purchases - and if a different name was used at some point in previous years, I haven't been able to find any references as to when it was renamed to "Apple ID".