名詞 sea level:

1. level of the ocean's surface (especially that halfway between mean high and low tide); used as a standard in reckoning land elevation or sea depth

形容詞 sea level:

1. lying below the normal level
   同義詞：low-lying, sea-level

1. The height of a thing above a reference level, especially above sea level or above the earth's surface.
   高度; 海拔在某個(gè)參考平面，特別是海平面或地面以上一個(gè)物體的高度
2. The top of this mountain is three kilometers above the sea level.
   這座山的山頂海拔三千米高。
3. This mountain is 1,400 meters above sea level.
   這座山海拔1,400米。