Nested options are essentially sub-options that fall under a main selection. Think of them as branches growing from a main tree trunk. In UI design, checkboxes are commonly used to represent these nested options. When users select a primary checkbox, additional related options may appear below it, often indented to visually signify their relationship to the main choice.

This is a tidy and intuitive way to offer users more control without overwhelming them with choices upfront. By using checkboxes for nested options, designers allow users to select multiple sub-options while still keeping the interface streamlined and user-friendly.