An Object List defines a list of field values that can be used when specifying Selection Criteria for filtering the data for your reports and extracts. A typical use might be to define all the transaction IDs that belong to a particular application system. Object Lists enable you to define a group of related values once, then use it in many reports by simply specifying the name of the Object List in your Selection Criteria. This avoids duplicating the same list of values in different reports.
For example, instead of specifying Select Statements that include transactions B001,B002,B003,..., you pre-define an Object List called BTRANS that has values B001,B002,B003,... Now when you specify the Select Statement, you simply specify BTRANS to include those transactions.