TraceAbove is an option for Trace and related functions which specifies whether to include evaluation chains which contain the evaluation chain containing the pattern form sought.
TraceAbove -> True includes the first and last expressions in all evaluation chains within which the evaluation chain containing form occurs.
TraceAbove -> All includes all expressions in these evaluation chains.
TraceAbove -> backward, forward allows you to specify separately which expressions to include in the backward and forward directions.
Using TraceAbove, you can see the complete paths by which expressions matching form arose during an evaluation.
See The Mathematica Book: Section 2.5.10.
See also: StackComplete.