Definition:Logical Connective/Unary

Definition
A unary logical connective (or one-place connective) is a logical connective whose effect on its compound statement is determined by the truth value of one substatement.

In standard Aristotelian logic, there are four of these.

The only non-trivial one is logical not, as shown on Unary Truth Functions.

Also defined as
Some treatments do not consider a unary connective to be a logical connective as such, because it does not actually "connect" anything, but this is a trivial point which can serve only to confuse.

Also see

 * Definition:Binary Logical Connective