An increment is an increase, either of some fixed amount, for example added regularly, or of a variable amount. For example, a salary may receive an annual increment. A decrease would rather be called a decrement.
Incremental may also refer to gradual change as opposed to massive, instant change.
Use in science and technology
Incremental changes are gradual improvements as opposed to revolutionary, paradigm-breaking changes - i.e. whereas the invention of inner tube tires was only an incremental change to wheels, the invention of the combustion engine was a revolutionary change over animal-drawn vehicles.
Use in programming languages
Incrementing is of constant use in computer programming, such as in loops that iterate through a set of items one at a time.
For example, in JavaScript, the increment operator works like the following:
x++
Where the decrement operator is:
x--
In addition, the increment operator can be written both as x++ and ++x, with separate meanings. For example: