This is the 2360th most frequent Chinese word.
公斤
Kilogram.
公斤 is used as the unit of weight to specify the weight of the watermelon.
这个西瓜重三公斤。
This watermelon weighs three kilograms.
公斤 is utilized to indicate the measurement unit for pricing apples by weight.
每公斤苹果的价格是五元。
The price per kilogram of apples is five yuan.
Although similar sounding, 公里 instead of 公斤 is used here—公里 refers to distance (kilometers) instead of weight (kilograms), which is distinct in measurement context.