The kiloliter (kL), which is more commonly spelled kilolitre outside of the US, is a unit of metric measurement that refers to volume. It is 1000 times the size of a liter, which is a more recognizable unit of measurement for small amounts of liquid. The hierarchy of ascending measurements in liter form is as follows: milliliter, centiliter, deciliter, liter, decaliter, hectoliter and kiloliter. Other larger and smaller measurements are used far less frequently.
The use of liters derives from metric systems developed in France, and the English name for liter is a close derivative of the French term, litron. The litron first became popular for use in France after the French Revolution and the measurement quickly spread to other countries. Precise definition of the liter and its multiples shifted over time. Presently, a liter is .001 cubic meters, but for a while it was not quite equal to this number. It wasn’t until 1964 that the General Conference on Weights and Measures (GCWM) decided to set and standardize an exact relationship between kiloliters and cubic meters that made them equivalent.
Given this shift, defining the kiloliter as a precise fit with cubic meter measurements hasn’t always been easy. Moreover, this measurement isn’t used often unless large amounts of volume are being assessed. With standardization though, the kiloliter is exactly equal to a single cubic meter, which makes math calculations and conversions simpler.
For those people who don’t use metric measurements often, it also helps to get a sense of kiloiters as translated to standard volume measurements, which are frequently used in places like the US. The kiloliter is equal to 33,814.02 fluid ounces, 4,226.75 cups, 2,113.38 pints, 1,056.69 quarts, 264.17 gallons, and 35.32 cubic feet. It's useful to think of the size of a kiloliter in halfgallon milk cartons. Essentially, over 500 full milk cartons are required to equal a single kiloliter.
The size of this measurement suggests that it is not practical for most everyday measuring tasks. Instead, it could be used to accurately discuss volume of large quantities of liquid. Figuring the amount of water in a lake or a stream could employ kiloliters as a measurement, or sometimes may still use cubic meters instead. The number of gallons of water in a pool could also be converted to kiloliter form. Release of huge amounts liquid pollutants or chemicals might also be measured in kiloliters.
Basically, kiloliters are metric measure of volume and one is equal to 1000 liters or a single cubic meter. They tend to be used for gauging high volume levels, which means most people won’t use this unit frequently for daily activities. Kiloliters easily convert to other metric measurements, and with a little work, they can also be converted to standard measurement systems.
Logicfest Post 2 
@Soulfox  The United States made a serious effort to switch to the metric system in the 1970s, remember? We know that effort failed but what is confusing is why it did.
That is a hard question to answer and requires some study. However, there are some obvious reasons why the switch wasn't made. Think about road maps, for example. We understand it is 30 miles or so to the next city, but how far is that in kilometers? Speaking of kilometers, if the speed limit is 70 miles per hour, what does that work out to in kilometers?
And, while talking about cars, how about gas? How many liters will that car hold? For those who obsess over
gas mileage, figuring out miles per gallon is easy enough, but what is the equivalent measurement in liters per gallon?
Those are a couple of example. The point is that converting to the metric system would be hard at first and then easy for subsequent generations. But which generation wants to bear the brunt of converting and having to rethink the way things have been measured for centuries? 


Soulfox Post 1 
This discussion brings up a question I have had since taking science classes in high school and college. Once you grasp the metric system, it is dead easy. Compare that to the English system of measurements used in the United States which is cumbersome as can be.
Why haven't we switched to the metric system in the United States? It makes no sense that we haven't done that. 