In principle, they are the names of two numbers: 5 (five) and 0 (zero). In addition to the football reference mentioned by colleague Jorge Luis Tovar Díaz, it can also be a fictional police department for a very popular television series in the 1970s called Hawaii Five-O, but which in Spanish was known as "Hawaii Five Zero", since in our language the letter /O/ and the number zero are not confused as it happens in English. At the time, producers were inspired for the name by Hawaii's recent addition as the 50th U.S. state.
