As a boy, I lived less than a block from a set of railroad tracks. The report of train whistles, and the low pitched sound of each train as it passed by during the night assured me commerce was underway, and all was fine. During the day, myself and others would often watch as a train passed to see what the oldest car was. The oldest was 1909 as I recall, and those cars looked very fragile. Of course the caboose was a punctuating symbol that defined the end of the train. I don’t ever recall a caboose at the front of the train. A caboose at the front of a train, before the engines, would be seen as something out of order, that is not being used as designed. Could one hook a caboose to the front of a train and have it operate? Sure—does it make sense–perhaps—but not as expected usage.
When I first became interested in electronics, resistors were the first component I encountered. Their resistance is measured in ohms. One might have 50 ohm resistor, or 68 ohm resistor, but when the value progresses into the thousands, the metric prefix Kilo is used. A 10 000 ohm resistor is a 10 Kiloohm resistor which is generally written as 10 KΩ, when the resistance becomes large enough we use Megaohms or MΩ. As people like to speak in shorthand, and everyone knows, that on an electrical schematic, resistors are in ohms, electrical engineers generally say “that’s a 4 K resistor,” implying that the value is 4 KΩ. When people say they are going to participate in a 5K run, it’s understood that it is a 5 Km distance.
The metric prefix Kilo- is supposed to modify the unit value that follows it, but in common usage, people often appear to use it as shorthand for a set of zeros. When the prefix symbol is moved next to a numeral, 5K becomes 5000; the prefix modifier becomes a suffix modifier. When it is thought of in this way, it can be used as a sort of stealth prefix for Ye Olde English, or whatever comes along.
For instance here is an example from the web where the metric modifier is separated from Olde English as if this is a good idea:
So it reads “Spruce beetles pick up where their pine cousins left off, eating through 136 000 acres in past year” rather than “Spruce beetles pick up where their pine cousins left off, eating through 136 Kiloacres in past year.” The prefix modifier becomes a suffix modifier and metric is “compatible” with anything. Just by removing a space we modify the leading number rather than the trailing unit. By invoking this idea, we create 5K dollars, or 75K crickets, or 210K albatrosses. This space removal causes a literary switcharoo that turns a prefix into a suffix. This appears to be a practice that has happened somewhat recently and has become an accepted part of the language. If there is no space between it and a leading number, the single metric “prefix” becomes a suffix number, and if there is a space then a metric unit must follow the prefix.
Is this usage a good idea? I’m not sure. Perhaps this is a usage that could make sense. Without a space 326K, or 326M, or 326G could be thought of as numbers. The value 326G certainly is more compact than 326 000 000 000. This distinction would have to be identified, formalized, and taught in schools, so that students would know how to use it properly. If one writes 25K they mean a number, if they write 25 K then one should expect a unit symbol to follow such as 25 Km, and 25 K would not be considered a finished statement. I can see how this usage could be useful, but currently it strikes me as the engine switched for the caboose.
The Metric Maven has published a book titled The Dimensions of The Cosmos. It examines the basic quantities of the world from yocto to Yotta with a mixture of scientific anecdotes and may be purchased here.