"Sea Grass" is a word in ENGLISH

A plant (Zostera marina), with very long and narrow leaves, growing abundantly in shallow bays along the North Atlantic coast.

Any plant of the order Naiadaceae, such as eelgrass, pondweed, etc.

A genus of plants of the Naiadaceae, or Pondweed family. Zostera marina is commonly known as sea wrack, and eelgrass.