Although you'll find many opinions out there, there's no precise set of criteria for determining what makes something a classic. For example, whether a particular movie or book is a classic largely depends on the opinion of the person watching or reading it.
If you think something is classic, that means you believe it is one of the best examples of a particular thing. For example, classic holiday movies are those movies that you believe are the best holiday movies ever made.
The word “classic" has its roots in two Latin words: classis and classicus. Classis referred to the five levels that Roman society was divided into. Classicus was the highest of these five classes. Thus, a classic is something at the top or in first place.
Some people might say calling something a classic is just a matter of opinion. They might be right. Opinion certainly does play a big role.
In fact, there are certain things that most people would consider classics precisely because of opinion. When enough people hold the same opinion — that something is a classic — then most people will consider it a classic, even if they don't personally find it to be worthy of the title.
For example, It's a Wonderful Life is a movie that nearly everyone would agree is a holiday classic. Not everyone would consider the movie a favorite, but so many people consider it to be a holiday classic that very few would argue its classic status.
If you look at things considered classics, you'll notice that most of them have a few things in common. Age is often a common factor. Classics tend to be older. They've been around a while and stood the test of time.
Not all classics have to be old, though. Sometimes a movie comes along that people consider an “instant classic." Even though it's newer, people love it so much that they immediately know that it will be one of those timeless movies that people will love for years to come.
Classics also often deal with universal issues about human nature that everybody can relate to. For example, books and movies that teach important life lessons in a way that touches the heart often achieve classic status because of their lasting significance over time.
Although whether something is a classic is open to individual interpretation, you can probably easily figure out which movies and shows you consider to be classics. If you have seen the show before, already know what is going to happen but still want to watch it, you're probably viewing a classic!