`@each` is a loop inSASS used to iterate over lists or maps. It allows you to apply styles dynamically based on the values in the list or map. For example,if you have `$colors: (primary: #3498db, secondary: #2ecc71);`, you can use `@each $name, $color in $colors { .#{$name} { color: $color; } }` to create classes for each color.