placeholder

A placeholder is a symbol, word, or string used to reserve space for content that has not yet been supplied. It indicates the type, format, or length of the expected content and is not intended as final data.

In software and web development, placeholders appear in user interfaces or templates and are replaced or removed when real content is provided. Common examples include placeholder text in input fields (for instance, a light-gray hint like “Enter your name”), and template strings containing placeholders such as {name}, {date}, or %s that are substituted at runtime. Placeholders help users understand what to supply and help developers illustrate expected formats during design and testing.

In databases, spreadsheets, and form design, placeholders serve as temporary stand-ins for values to be filled in later, aiding layout and validation. In programming, placeholder variables hold temporary values or stand in for unknowns until actual data is available, and they are often replaced or discarded as code runs.

In mathematics and science, placeholders are symbols (such as x or y) used to represent unknown quantities to be solved. In typography and publishing, placeholder text like lorem ipsum demonstrates layout and typography before the final content is ready. In graphic design, placeholder images or graphics fill space in drafts and proofs.

Best practices include replacing placeholders before publishing or releasing a product, ensuring accessibility for users, and using descriptive placeholder text to reduce ambiguity. See also placeholder text, template, variable, mock data, lorem ipsum, and form field.