Input is usually related to user input, i.e., to the data that user supplies to a running application. In many systems this input is considered to be potentially dangerous and needs to be sanitized to ensure that the user has not injected runnable code into the application.
For questions pertaining to the HTML <input> tag, please use html-input instead.
Input is any form of information that is provided to an application or process. In interactive graphical user interface (GUI) applications, input is often taken from the user via input controls such as textboxes and drop-down lists. In non-interactive services, input is often taken from local or remote resources, or service requests.
