[re.sid.u.al] n [L residuum residue] (1557) 1: remainder, residuum: as a: the difference between results obtained by observation and by computation from a formula or between the mean of several observations and any one of them b: a residual product or substance c: an internal aftereffect of experience or activity that influences later behavior; esp: a disability remaining from a disease or operation
2: a payment (as to an actor or writer) for each rerun after an initial showing (as of a TV show)
[2]residual adj (1570) 1: of, relating to, or constituting a residue
2: leaving a residue that remains effective for some time -- re.sid.u.al.ly adv