What is the old sea dog in Treasure Island?

In "Treasure Island," the old sea dog refers to Long John Silver, a central character in Robert Louis Stevenson's novel. He is a cunning and charismatic pirate who serves as the cook on the Hispaniola and later reveals his true nature as a leader of a mutiny. The term "sea dog" traditionally refers to an experienced sailor or pirate, and Silver embodies this archetype with his blend of charm, ruthlessness, and cunning. His complex character adds depth to the story, making him both a mentor and an antagonist to the young protagonist, Jim Hawkins.