RecordLists

RecordLists is an option for ReadList which specifies whether objects from separate records should be returned in separate sublists.

With the default setting RecordSeparators -> {"\n"}, setting RecordLists -> True makes RecordLists return objects that appear on different lines in different sublists.

With RecordLists -> False, ReadList returns a single list of all objects it reads.

With RecordLists -> True, ReadList returns a list containing a sublist for each record.

See The Mathematica Book: Section 2.11.8.