牢

Core sense is containment or enclosure:

1. Livestock Pen/Stable: Specifically the enclosure of cattle or pigs; common in agricultural or ritual contexts.

2. Human Confinement: Prison, jail, or dungeon.

3. Stability/Security: Secure, firm, or steadfast (stability derived from being "locked down" or immovable).

• Noun: A physical enclosure (pen, jail).
• Adjective: Secure; tight; immovable.
• Verb: To confine or lock up.

Contrast with 獄 (yù): 牢 refers specifically to the physical architecture of confinement (walls and bars), whereas 獄 generally refers to the judicial process, legal case, or trial.

The presence of the roof radical (宀) indicates a structured enclosure.

Because the glyph implies a structure, if the context suggests open-air restraint or simple binding (e.g., with rope), verify if another term such as 縛 (fù) is more appropriate.