An operation that has only one input.
Example: the square root function.
√(16) = 4 has just one input "16" to produce an output of 4
There are many more: factorial, sine, cosine, etc. are all unary operations.
A "binary operation" has two inputs.
Example: the plus operation is a binary operation: 3+5 has two inputs ("3" and "5") to produce an output of 8
Definition of
Unary Operation
See: Binary Operation