leaving a residue that remains active or effective in air, soil, etc for some time

residual pesticides

something left over; a remainder

in statistics, the difference between a result obtained by observation and one calculated from a formula, or between the mean³ (average) of a set of observations and any one of them

(also in pl) a payment made to an actor, musician, etc when a film, television programme, or other work they were involved in is rerun after the first showing