While the term "livery" can have many meanings, in cruise ship lingo it refers to the specific design and paint scheme used on the ship's exterior. As an example, think about the "livery" of UPS' brown delivery vehicles with a yellow logo. It is what makes the company's vehicles identifiable around the world, whether the vehicle in question is a van, a motorcycle or a boat on the canals of Venice.
Apply the same principle to cruise ships and you begin to see the patterns that distinguish one cruise line's ships from another's, even from a distance. The livery includes specific paint colors and variations of the company’s logos and symbols. The company's livery design may change slightly from one ship to another, or from one class of ships to another.
Norwegian's livery is known for its signature artistic bow designs, which include everything from mermaids to gemstones. In 2017, Princess changed its livery to include the bright blue waves from its logo streaming from the bow of the ship. Holland America, Celebrity and even Disney use simpler nautical color schemes.
Often new liveries appear first on new vessels, followed by older ships as they go to dry dock for refurbishments.