Alphanumeric means alphabetic or number characters are valid entries. For example, if a data element is defined as a 12-character alphanumeric, it could contain any 12 letter … or number characters: abzy1298pqrs.lphanumeric means alphabetic or number characters are valid entries. For example, if a data element is defined as a 12-character alphanumeric, it could contain any 12 letter … or number characters: abzy1298pqrs.