A more thorough explanation:

The Federal Trademark Act, also known as the Lanham Act, is a law that was passed in 1946. It establishes a national system for registering trademarks and protects the owners of federally registered marks from the use of similar marks that could cause confusion or dilute the strength of a strong mark. This law is separate from and works alongside state common law.

Let's say a company called "ABC Toys" has a federally registered trademark for their logo, which features the letters "ABC" in a specific font and color scheme. Another company, "XYZ Toys," starts using a similar logo with the letters "XYZ" in the same font and color scheme. This could cause confusion for customers who may think the two companies are related. Under the Lanham Act, ABC Toys could take legal action to protect their trademark and prevent XYZ Toys from using a similar logo.