Definition:Logical Connective/Unary

Definition
A unary logical connective (or one-place connective) is a 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 unary connectives to be logical connectives as such, because they do not actually "connect" anything, but this is a trivial point which can serve only to confuse.

Also see

 * Binary Logical Connective

Linguistic note
The word unary is pronounced yoo-na-ry.