(sports) A rule in some sports that allows players to enter and leave the game for other players many times during the course of the game, and for coaches to bring in and take out players an unlimited number of times.

plural of blood substitution

(rugby) A temporary substitution for a visibly-bleeding player who must leave the field of play for first-aid treatment.

plural of substitution cipher

(theology) The theory of atonement which holds that Jesus died on the Cross in place of human sinners.

(linear algebra) A method of solving linear systems that have been transformed into row echelon form. / (combinatorics) A method of solving recurrence relations.

plural of back substitution

(Scotland) The acting sheriff in a Scottish county or city, like the sheriff-depute appointed by the Crown, but unlike the sheriff-depute forced to reside within his judicial district, and forbidden to take other employment.

(economics) a good that a consumer perceives as similar to another good, which decreases the demand for that other good

(chemistry) in aliphatic organic chemistry, a form of substitution reaction in which the leaving functional group is replaced with a nucleophile