Or

is a dyadic scalar boolean function which tests if at least one of the two arguments is true: it returns 1 if at least one side is 1 and 0 if both are 0. It represents the logical disjunction in Boolean logic. In many APLs, Or is a special case of the GCD function.

Examples
The following shows all possible combinations of inputs as a Boolean function.

When combined with Reduce, Or can be used to test if some value in a Boolean vector is true.

Documentation

 * Dyalog
 * APLX
 * J Dictionary, NuVoc