"To book a cruise" means to make a reservation or purchase tickets for a vacation on a large ship that travels in the sea or other bodies of water. Full definition
When booking a cruise at eligible companies, a $ 500 credit is awarded. (lendedu.com)
He prefers to book cruises with at least a day of sailing between ports. (moneysense.ca)
I wouldn't necessarily book a cruise through an airline but, if they want to give me one for free, I'm willing to submit an email address. (insideflyer.com)