R-rated movies are those that require adult supervision for viewers under the age of 17. However, the term "R-rated" is not the only way to indicate mature content in entertainment. There are a few synonyms that can be used interchangeably, such as "restricted," "adults-only," "mature audiences," or "age-restricted." Other terms that are similar in meaning include "X-rated," "NC-17," and "unrated." While the specific guidelines for each rating may differ, they all share a common theme of containing content that may not be appropriate for younger audiences. It's important to pay attention to these ratings when selecting entertainment to ensure that it aligns with individual values and preferences.