The translated modern English version of the bible referencing a thousand years doesn't mean 1000 years in English. It more closely references an uncertain amount and a lot of time. “Chilioi” seems to have an unknown length of time attached to it or perhaps the meaning is an all encompassing completeness rather than a literal meaning of time. Revelation 20:2-6 “And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a THOUSAND years.” The Bible has been translated several times and the original language is actually lost.
People all over the world describe money in the tens or hundreds of thousands with a K after it. $435,000 becomes $435K. The simple answer is that Kilogram means Thousand. The more complex answers is that the French took the Greek word for thousand "Chilioi" and shortened it to "Kilo" and then made new words like Kiloliter, Kiliwatt, Kilogram, Kilotonne, etc. The abbreviation KG for Kilo references Kilograms and means 1000 grams. Anything Kilo can be extended to multiply a quantity by 1000. Hence why we use the letter K in shorthand to describe Thousand.