I know I have seen jobs posted that pay $50K, and K is meant to stand in for a thousand. And you would be correct, thanks to the Greeks. K comes from the Greek word kilo which means a thousand.

K is the unit symbol for the kelvin, used to measure thermodynamic temperature (note: degree sign is not used with this symbol). K is the chemical symbol for element potassium (from its Latin name kalium).

K comes from the Greek word kilo which means a thousand. The Greeks would likewise show million as M, short for Mega. So if we stay consistent with the Greek abbreviations, then billion would be shown as a letter G (Giga). Think of your computer expressing bytes of memory as kilobyte, megabyte, or gigabyte.

In late Latin and the early Romance period the unvoiced velar, represented by C, became palatalized before front vowels, and in the 12th century K was reintroduced as a substitute for C to represent the velar before front vowels since C did duty for both the velar and palatal in such cases and confusion was thus liable ...