5-thread is a type of sewing thread that consists of five individual strands twisted together. This construction provides added strength and durability, making it suitable for various sewing projects, including heavy fabrics and outdoor gear. The thickness of 5-thread can vary, allowing it to be used in both hand and machine sewing. In the context of serger machines, 5-thread refers to a specific stitch type that combines two needle threads and three looper threads. This stitch is often used for overlocking, which helps to prevent fabric edges from fraying while providing a professional finish to seams.