A darning needle is a large sewing needle with a big eye (the hole at the top) used for mending holes in fabric, especially in socks and sweaters. When clothes develop holes from wear, darning involves weaving thread back and forth across the gap to fill it in, almost like creating new fabric. The needle needs to be large and sturdy enough to carry thick thread through multiple layers.

Before inexpensive factory-made clothing became common, people darned their worn clothes regularly instead of throwing them away. A skilled person could make a darned patch so neat it was barely noticeable. Today, some people still darn their favorite items rather than replace them, finding satisfaction in extending the life of something they care about.

In some parts of the United States, the term darning needle also refers to a dragonfly, probably because the insect's long, thin body resembles a sewing needle. This nickname shows how people often name things in nature after familiar tools and objects from daily life.