An alias or alternate name (sometimes also listed as AKA “Also Known As”) is a variation of the legal name of an individual. It appears on legal documents, not in family records. See “Nickname.”
Ancestry will create an alternate name when a record is saved that contains a name that is different from the current profile’s name.
For example, if you save a record that was listed as “John A. Morgan” to the profile of “John Morgan” an alternate name “John A. Morgan” is created. If you save a record listed as “John A. Morgan” to the profile of “John Andrew Morgan,” an alternative name is not created since the initial is assumed by the profile name.