What is the weight of 1000 grains of a crop called, which serves as a standard index of seed boldness and density?

'Test Weight' is the weight of 1,000 seeds (e.g., ~40 grams in wheat, ~21 grams in basmati rice, ~2 grams in Phalaris minor). The weight of 100 bold seeds (like gram or maize) is called the 'Seed Index'.