Kilo
Kilogram, Kilometer, Kilowatt
noun, suffix
キロ comes from kilo, and it can mean kilogram, kilometer, or any unit that starts with "kilo" in English.
You can also use abbreviations like "kg" and "km" in Japanese, and they're often just pronounced キロ too.
一ヶ月で五キロやせました。
I lost five kilos in one month.
うちから学校まで、大体３キロです。
It is roughly 3 km from our house to the school.
この石は、キロ当たり１円にしかなりません。
This stone sells for only one yen per kilo.