boolean operation: an operation that follows the rules of Boolean algebra; each operand and the result take one of two values
operation: (computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)
diphtheria: acute contagious infection caused by the bacterium Corynebacterium diphtheriae; marked by the formation of a false membrane in the throat and other air passages causing difficulty in breathing