What is the ghosted graphic that is displayed on top of or behind text in a document called?

The ghosted graphic displayed on top of or behind text in a document is commonly referred to as a "watermark." Watermarks are often used to indicate the status of the document, such as "Draft" or "Confidential," or to enhance branding by including logos or images. They are typically semi-transparent, allowing the text to remain readable while still being visible.