noun
International Prototype of the Kilogram; IPK
Technical term in metrology; refers to the physical artifact that defined the kilogram until 2019.
国際キログラム原器はパリの国際度量衡局に保管されていた。
The International Prototype of the Kilogram was kept at the International Bureau of Weights and Measures in Paris.
Compound of 国際 (international), キログラム (kilogram), and 原器 (prototype/standard instrument).