downward/'daʊnwəd $ -wərd/

a. moving from a higher position to a lower one

ad. [or ~s] towards a lower position

a. [仅置于名词前] 向下的：a downward slope of a hill 山的下坡

ad. [或~s] 向下：The plane flew downward(s). 飞机往下飞。

构词down + ward

用法一般用downwards作副词，downward作副词用主要是美语用法。