毫

• Physical: Fine, downy hair or whiskers; distinguished from general hair/fur by its delicacy (e.g., fuzz or soft bristles).
• Measurement: A literal minute unit of length (traditionally a fraction of a cun 寸), or used rhetorically to denote an infinitesimal amount or degree.
• Technical: The tip or bristles of a writing brush, emphasizing the precision of the stroke.

• Quantifier of Negation: Used with negatives (e.g., 毫無, 不毫) to create an absolute negative, translating as "not in the slightest," "not at all," or "without a trace."

• vs. 毛: While both refer to hair, 毫 emphasizes precision, fragility, or insignificance.
• vs. 微 and 纖: Where 微 suggests something nearly invisible or microscopic, and 纖 suggests a slender, thread-like quality, 毫 emphasizes point-like or textural minimalism.

• Fanqie reading: 胡刀
• Tang-period reading: hɑu

Determine if the context is biological (down/whiskers), quantitative (a literal measure vs. an idiomatic "slightest bit"), or technical (the brush-tip in calligraphy). If it appears alongside a negative, treat it as a marker of absolute absence.