下げる
さげる · sageru · JLPT N4 · verb-ichidan
to lower
⬇️ 下 = down + げる: make it go down; sageru sounds like sag
下 means down, and the -eru ending marks the transitive verb: you lower something. Its partner 下がる (sagaru) is the intransitive one, where something goes down on its own. Sageru starts like sag: what you lower or hang sags downward.
下 — horizontal line 一 + mark below
下 is an indicative character: a long horizontal line represents a reference level, and a shorter stroke placed beneath it points to the area below. The original meaning 'below, down' comes directly from this spatial diagram, and it later extended to verbs like 'descend' and 'lower'.