Definitions
1.NounA line to which a drowning or falling victim may cling.
2.NounA source of salvation in a crisis.
3.NounA means or route for transporting indispensable supplies.
4.NounA system or structure of vital importance to a community.
5.NounOn the deck of a boat, a line to which one can attach oneself to stay aboard on rough seas.
6.NounA line from the diver to a tender at the surface control point.
7.NounA particular crease in the palm.