noun, punctuation · a small, slender pointed tool used for sewing, acupuncture, or as a pin

他在地毯上找一根掉落的针。

noun · a medical shot or treatment administered through a syringe

生病时打一针会好得快一些。

noun · a single loop of thread in sewing or the unit of closure in a surgical wound

由于伤口太深，医生给他缝了四针。