No Copyright Protection for Titles
First, know that copyright law does not protect titles. Titles are too short to qualify for copyright protection.
No Trademark Registration for the Title of a Single Work; Maybe for the Title of a Series
In certain circumstances, trademark law can protect titles. However, the title of a single work is not eligible for federal trademark registration. In contrast, the title of a series is eligible for federal trademark registration.
Other Ways to Protect the Title of a Single Work
Secondary Meaning. Even though the title of a single work is ineligible for trademark registration, the title of a single work may nevertheless obtain some protection under federal trademark laws if the title has developed secondary meaning.
Secondary meaning exists when "the title is sufficiently well known that consumers associate it with a particular author's work”. It is okay if the "particular author" is unknown, as long as consumers believe the mark refers to a "single source, even if that source is anonymous." When determining the existence of secondary meaning, courts look at factors such as the scope of sales and advertising, length of use, the number of sales, and the number of customers.
Here are examples of titles determined by courts as having secondary meaning:
Bridge on the River Kwai. A 1957 film that was viewed by millions of people, won several Academy awards, and was the 58th highest grossing motion picture of all time (at the time of the court's analysis in 1998).
The Book of Virtues. This 1993 book authored by William Bennett and published by Simon & Schuster was on The New York Times bestseller’s list for 88 consecutive weeks, sold more than 2.2 million hardcover copies, was an alternate selection for "The Book of the Month Club", and was advertised extensively in national publications .
Top Gun. This film had advertising expenditures in excess of 17 Million Dollars and grossed 72 Million Dollars within the first 72 days of its release in United States theaters.
Unfair Competition. Protection of a single work may also be available under state unfair competition laws. Unfair competition refers to fraudulent, deceptive, or dishonest business practices.
Most states have laws forbidding "passing off," a form of unfair competition. In colloquial terms, passing off laws prohibit a person from using a deceptively similar title to your movie/book/song’s title in a fraudulent attempt to siphon the good will you have established in the product.