The term 'Cheerio' is a British expression used as a friendly FAREWELL. It can be seen in the crossword solutions given, which include 'FAREWELL' (8 letters), 'GOODBYE' (7 letters), 'ADIEU' (5 letters), 'Tata' (4 letters), 'BYE' (3 letters), 'Toodles' (7 letters), 'ADIOS' (5 letters), and 'Seeya' (5 letters). All of these terms are used to express a fond FAREWELL to someone. Additionally, 'Pippip' (6 letters) is another term that is used in a similar way.