What is lifeline?

Lifeline means a person or thing is very important for some another person that he/she depends on.Salvation, life line, help, line-of-life, rope, helping-hand, line, careline and aid are the synonyms of lifeline.Here ate some of the sentences that can relate lifeline are as follows:

1.For many old people their telephone is a lifeline.

2.He clung to the lifeline and the woman pulled him towards the bank.

These are some relatable sentence for the lifeline.