甾

zāi

巛 + 田

Definitions

zāi steroid nucleus

Etymology

Pictograph of a container made out of bamboo. Variant of 𠙹.

About

甾 (zāi) began as a pictograph of a bamboo container for storing liquids (a variant of 𠙹), but modern chemistry has entirely repurposed it to denote the carbon ring structure of steroids and sterols. In this new role, it is read visually rather than phonetically or semantically: the top 巛 (chuān) stands for the three side chains, and the bottom 田 (tián) for the four fused carbon rings of the steroid skeleton. Thus, the ancient character's physical geometry becomes a diagrammatic tool for precise chemical nomenclature.