ALEX MORGAN WORKOUT ROUTINE DIET PLAN on trace n. 1. see MEMORY trace. 2. in multivariate statistics and linear algebra, the sum of the elements on the MAIN DIAGONAL of a SQUARE MATRIX. trace conditioning a procedure in classical conditioning in which a conditioned stimulus and an unconditioned stimulus are separated by a constant interval (called the trace interval), with the conditioned stimulus presented first. Compare temporal conditioning. ALEX MORGAN WORKOUT ROUTINE DIET PLAN 2016.