delta
noun uk/ˈdel.tə/ us/ˈdel.t̬ə/
(RIVER)
[ C ] geography 三角洲
an area of low, flat land, sometimes shaped like a triangle, where a river divides into several smaller rivers before flowing into the sea
the Mississippi delta 密西西比河三角洲
the delta of the Nile 尼罗河三角洲
(LETTER)
[ C or U ] language, mathematics, science (symbol Δ, δ)（希腊语字母表的第四个字母）
the fourth letter of the Greek alphabet