What does Diagonal pliers mean? - definitions- bent needle nose pliers meaning in english grammar ,Definition of Diagonal pliers in the Definitions.net dictionary. Meaning of Diagonal pliers. What does Diagonal pliers mean? Information and translations of Diagonal pliers in the most comprehensive dictionary definitions resource on the web. Wikipedia (0.00 / 0 votes) Rate this definition:Pliers - definition of pliers by The Free DictionaryDefine pliers. pliers synonyms, pliers pronunciation, pliers translation, English dictionary definition of pliers. pliers top: needle-nose bottom: slip-joint also ply·er n. 1. One who plies a trade.