"If an end gets absent in the fabric for a short in length in the fabric, then this kind of defect is termed as a broken end". See below graphic.
"If the end gets absent for long in length in the fabric, then this defect is called missing end". See below graphic.
Possible causes of this defect are poor yarn quality (strength, the degree of yarn twist, elongation, hairiness and yarn imperfection), improper selection of drop wires, improper setting of warp stop motion, dirt deposition on the drop wire and electrodes of warp stop motion.