1. Physics(Material Noun-Neuter) a piece of fine-grained dark schist or jasper formerly used for testing alloys of gold by observing the colour of the mark which they made on it. সোণ পৰীক্ষা কৰা শিল।

English: touchstone,
Assamese: কষ, কষটি, কষটি-শিলা, নিকষ,
Hindi: कसौटी