lifeline

noun

1. A line to which a drowning or falling victim may cling.
2. (broadly)A source of salvation in a crisis.

   “The girls, of course, were my lifeline during this time.”

   “Slowly I began to fill up some of the emptiness inside—writing had become my lifeline.”

   “The Government has thrown a lifeline to Alstom's Derby Works, with an offer of an order for ten Class 345 nine-car electric multiple units (EMUs) for the Elizabeth line - but only if the 'price is right'.”

3. A means or route for transporting indispensable supplies.

   “Planners did not see the access routes as west Berlin's sole lifeline, which now seems instinctive to us.”

   “It is no real surprise that half the UK's stations and 5,000 miles of route were recommended to close. Nevertheless, some great mistakes were made in Marples' devil-may-care purge that left commuters stranded and seaside resorts without a lifeline.”

   “Oil and liquefied natural gas tankers moving through the Strait of Hormuz carry around 20% of the world’s supply. But for countries on the Persian Gulf, the waterway is more than just an energy route – it’s a lifeline for more than 100 million people.”

4. A system or structure of vital importance to a community.
5. On the deck of a boat, a line to which one can attach oneself to stay aboard on rough seas.
6. A line from the diver to a tender at the surface control point.
7. A particular crease in the palm.