Sabine's gull treated as comprising a monotypic genus; it is only placed within the genus "Larus" when the genus is enlarged. The black bill and notched tail are almost unique within the gulls, as they are shared only with the swallow-tailed gull of the Galapagos. On the basis of this the two species were often thought to be each other's closest relatives, a hypothesis ruled out by a number of behaviour and ecological differences. Mitochondrial DNA studies confirmed that they are not closely related, and the closest relative of the Sabine's gull is now thought to be the ivory gull, another Arctic
Four-letter word letters. Typical examples include the word "work", implying that work can be unpleasant, or the game of "golf", jokingly referred to as a four-letter word when a player's pastime becomes an exercise in frustration. "Charlotte Observer" journalist Doug Robarchek noted in 1993 how many politicians have names with four letters, "Ever notice how many U.S. politicians have names that are also four-letter words? Ford, Dole, Duke, Bush, Gore ... and how many make us think of four-letter words?" Four-letter word The phrase four-letter word refers to a set of English-language words written with four letters which are considered profane, including