須

• Modal necessity: "must," "have to," or "it is necessary that."
• Temporal duration: "a moment," "a brief interval," or "to wait" (e.g., in the compound 須臾).
• Physical attribute: "whiskers" or "beard."

Typically functions as a modal auxiliary preceding the verb (須 + Verb).

Often interchangeable with 必, though 須 frequently emphasizes the requirement or prerequisite condition that must be met.

• In early texts, 須 was the standard form for facial hair before the specialized character 鬚 (adding the hair radical 髟) was developed.
• The glyph 需 is often interchangeable with 須 in early texts, though 需 can carry specific connotations of demand, supply, or waiting.
• Simplified variant: 须.

There may be a semantic bridge between the temporal sense ("to wait") and the modal sense ("it is necessary"). If a passage feels ambiguous between a requirement and a pause, consider whether the author is intentionally playing on the necessity of waiting.