1. things that are essential for survival or success; vital sources of support
2. ropes or cables used for safety, especially to prevent falling or to rescue someone
Usage: nautical; safety equipment
3. lines on the palm of the hand, traditionally believed to indicate length of life
Usage: palmistry

Examples

• Small businesses are the economic lifelines of many rural communities.
• The charity provides lifelines to families struggling with poverty.
• Mountain climbers always carry lifelines in case of emergency.
• The ship’s crew threw lifelines to the passengers in the water.
• The fortune teller examined the lifelines on my palm.
• Internet access has become one of the essential lifelines for remote workers.