• 下した — below; under
• 下さがる — to go down
• 下ください — please (polite request)
• 地下ちか — underground
• 下手へた — unskilled
• 以下いか — less than; under
• 下山げざん — descent from a mountain
• 下町したまち — downtown
• 目下もっか — at present

“下” visually depicts something below a line — indicating downward direction or position. It’s used in location (e.g., under), comparison (e.g., lower rank), and motion (e.g., to go down). It’s also key in respectful language forms such as “ください”.

気温きおんが 下さがりました。
The temperature has dropped.

地下鉄ちかてつで 会社かいしゃに 行いきます。
I go to the office by subway.