泻湖岛
环礁
内岛

lagoon \la*goon"\ (l[.a]*g[=oo]n"), n. [It. or Sp. laguna, L.
lacuna ditch, pool, pond, lacus lake. See {Lake}, and cf.
{Lacuna}.] [Written also {lagune}.]
1. A shallow sound, channel, pond, or lake, especially one
into which the sea flows; as, the lagoons of Venice.

2. A lake in a coral island, often occupying a large portion
of its area, and usually communicating with the sea. See
{Atoll}.

{Lagoon island}, a coral island consisting of a narrow reef
encircling a lagoon.