1a contest for the position of champion in a sport or game:the final round of the championship will be in Japanthe team’s final match before the European championships [with modifier]:the world chess championship [as modifier]:a championship course
the position or title of the winner of a championship contest:Louise Gibson retained the women’s championship
(the Championship) the second division of professional soccer in England and Wales.
2 [mass noun] the vigorous support or defence of a person or cause:Alan’s championship of his estranged wife
championship in other Oxford dictionaries
Definition of championship in the US English dictionary