Source : WordNet®

lifeline
     n 1: a crease on the palm; its length is said by palmists to
          indicate how long you will live [syn: {line of life}, {life
          line}]
     2: support that enables people to survive or to continue doing
        something (often by providing an essential connection);
        "the airlift provided a lifeline for Berlin"; "she offered
        me a lifeline in my time of grief"
     3: line that raises or lowers a deep-sea diver
     4: line thrown from a vessel that people can cling to in order
        to save themselves from drowning