(bound form) used in 渤海 bó​hǎi for the Bohai Sea; also known as the Gulf of Zhili or Chihli

(literary) used in ancient geographical names to refer to the seaside or a branch of the sea, specifically in the ancient name for the Bohai Sea 勃澥 bó​xiè

(literary) used to describe the vast changes in the world over time, specifically as a shortening of 沧海桑田 cāng​hǎi​sāng​tián