命綱

1. Origins, structure, and basic meaning

• Structure: 命綱 is read as いのちづな and can mean “lifeline” or “safety rope”, depending on context.
• Basic usage: The examples show a safety rope checked before high work and a generator serving as a lifeline.

2. Common pitfalls and similar expressions

• Distinguishing senses and uses
  • It literally means a rope preventing a fatal fall and figuratively any crucial last resource that keeps life or operations going.