A selector refers to any element to which designated styles are applied. A rule is a format instruction that consists of a specified selector and the properties and values applied to it. A declaration consists of a property and its value. To define multiple declarations for one selector within a rule, you must separate each declaration with a semicolon. Except when declaring inline styles, you must place properties and their values within curly braces. If you want a particular rule in a style sheet to be ignored, you can create a comment by placing code in between the /* and */ characters. The style you define will flow, or cascade, throughout your documents, unless another style defined inside of a page specifically overrides it. This concept is known as inheritance.