RORY: Oh, the essay – the big kahuna.
The “big kahuna” is an idiomatic phrase meaning “the boss, the leader, the head of an organisation, the big one”. It’s borrowed from Hawaiian, where the word kahuna means an expert in any field, but is often thought of as referring to a shaman or high priest.
The term became known from the 1959 comedy film Gidget, in which “The Big Kahuna”, played by Cliff Robertson, was the leader of a group of surfers [pictured]. Beach party movies of the 1960s often used the term, such as Beach Blanket Bingo, where “The Big Kahuna” was the best surfer on the beach.
The Annotated Gilmore Girls 