A seawall is a strong wall built along the edge of the sea, so the water cannot wash onto the land or eat away the shore. You see them in towns by the sea, along harbours, and in places where storms push the water high.

A seawall is a strong wall built along the edge of the seaSeawall是一道沿著海邊蓋的堅固牆, so the water cannot wash onto the land or eat away the shore目的是讓海水沖不上陸地，也侵蝕不了海岸。You see them in towns by the sea, along harbours你會在海邊城鎮、港口沿岸看到它們, and in places where storms push the water high也會在暴風把海水推得很高的地方看到。

It is simply the ordinary words sea and wall stuck together; English has had this compound for a very long time (Old English already had sǣweall).

It is simply the ordinary words sea and wall stuck together它就只是sea（海）和wall（牆）這兩個普通字拼在一起; English has had this compound for a very long time英文有這個複合字已經很久了 (Old English already had sǣweall)（古英文早就有sǣweall這個字）。

Though actually, people sometimes use seawall and breakwater as if they were the same thing. A seawall usually stands on the land’s edge to keep the sea off. A breakwater more often stands out in the water to break the waves before they reach the shore.

Though actually不過其實, people sometimes use seawall and breakwater as if they were the same thing有時候人們會把seawall和breakwater當成同一件事來用。A seawall usually stands on the land's edge to keep the sea offSeawall通常立在陸地邊緣，用來擋住海水。A breakwater more often stands out in the water而breakwater比較常立在海裡面, to break the waves before they reach the shore在浪到岸邊之前先把它打散。