"How many people on cruise" is a noun phrase that refers to the number of individuals aboard a cruise ship. For instance, a cruise ship with a capacity of 5,000 passengers would have 5,000 people on cruise.
Knowing how many people are on a cruise is important for safety, security, and planning purposes. It helps cruise operators manage resources, provide adequate amenities, and ensure the well-being of passengers. Historically, cruise ships have evolved to accommodate more people, with the largest ships today carrying over 6,000 passengers.