atoll comes from Dhivehi (Maldivian) atoḷu ('atoll'), referring to the ring-shaped coral formations of the Maldives, introduced into English in the early 19th century. The path is chiefly one of transmission: an older form is taken into English, with the word's shape and meaning carried through the language names and forms preserved in the history. In modern use, the noun sense is "a ring-shaped coral reef or island enclosing a lagoon", which keeps the etymology connected to the word's present dictionary value rather than treating it as a merely historical label. Its nearest semantic neighbors include reef, coral island, islet, but the etymology gives the word its own historical profile within that field. The principal historical forms in the chain include Dhivehi atoḷu, which anchor the explanation in named linguistic material.