庚

The seventh of the Ten Heavenly Stems (天干). In contexts involving astrology, early medicine, or the Five Elements (Wuxing), it is associated with Yang Metal (金), which may serve as shorthand for:

• The West (direction)
• Autumn (season)
• Attributes of hardness, rigidity, or "killing energy" (severity)

Typically functions as an indexical marker—a label used in dating, sequencing, or naming. In these roles, it has no independent semantic value beyond its position in the cycle.

This glyph is phonetically identical to 更 (gēng), meaning "to change," "to replace," or "further." In very early texts or specific scribal traditions, 庚 may appear as a phonetic loan for 更. If the indexical reading creates a semantic impasse, test the glyph as a verb (to alter/replace) or an adverb (further/more).