residual

1. n. In statistics, the difference between an observation and a prediction of the observation using a mathematical model. 2. n. In statistics, the proportion of variance in a dependent or quasi-dependent variable not accounted for by experimental variables and usually attributed to random error. 3. adj. Denoting symptoms remaining after an acute attack of a disease or disorder has mostly subsided, as in residual symptoms of schizophrenia. 4. n. In general, anything remaining after some portion has been removed or used up.