"Read-Only" refers to a mode of access where users can view data or files but cannot modify or delete them. This is commonly used in computer systems to protect important information from accidental changes. For example, a PDF document can be set to read-only, allowing users to read its content without altering it. In many software applications, read-only settings help maintain the integrity of data. For instance, a spreadsheet may be shared in read-only format so that multiple users can view the information without risking unintentional edits. This feature is essential for collaboration and data security.