渡す
わたす · watasu · JLPT N5 · verb-godan
to hand over
🌉 wata-su: WATer crossing, then pASS it to the other side
The kanji 渡 has the water radical 氵 on the left: its core sense is crossing water. 渡す is the transitive partner of 渡る (to cross), so it means making something cross over, which is how it comes to mean handing a thing across to someone.
渡 — water radical 氵 + 度 (measure/cross)
渡 combines the water radical 氵 with 度, which provides the sound and suggests measuring or passing across. Originally it meant to cross a body of water, like fording a river or ferrying across. Over time it broadened to mean 'to pass through' any transition, including time or stages of life.