In contemporary English usage, the letter 'K' is employed to denote a thousand, a convention often observed in expressions like 10K or 20K, signifying 10 thousand or 20 thousand. The choice of 'K' over 'T' for representing thousand has a historical origin rooted in the Greek word 'Chilioi,' meaning thousand. Initially, 'K' was exclusively utilized in the Greek language to denote a thousand.

While 'K' doesn't signify the complete count of 1000, it conveys a multiplier for thousands, a concept also found in biblical references. The French language embraced this term, eventually evolving into 'Kilo.' Consequently, 'kilo' came to symbolize a thousand, used in various contexts such as kilograms for 1000 grams, kilometers for 1000 meters, and kiloliters for 1000 liters.

In essence, 'K' is employed as an abbreviation for 'Kilo,' designating a factor of 1000. Hence, the usage of 'K' in expressions like 10K or 50K stems from its association with 'kilo,' providing a distinct symbol for a thousand. This clarifies why 'K' is utilized instead of 'T' when expressing values in thousands, underscoring its connection to the metric system prefix 'kilo.'

This choice to represent a thousand with 'K' rather than 'T' has its roots in the historical evolution of the term 'kilo' and its adoption into various languages. The term 'kilo' was originally derived from the Greek word 'Chilioi,' which exclusively referred to a thousand in the Greek language. As the concept of 'kilo' spread, it became associated with multiplying quantities by a thousand, leading to its adoption in the metric system.

In modern usage, the metric system utilizes 'kilo' as a prefix, denoted by 'K,' to represent a factor of 1000. This adoption has influenced not only scientific and technical fields but also everyday language. Hence, when expressing numerical values in the thousands, the symbol 'K' is often used to indicate this metric system convention.

In summary, the use of 'K' for a thousand is deeply intertwined with the historical and linguistic development of the term 'kilo.' This connection provides a clear explanation for why 'K' is employed instead of 'T' when expressing values in thousands.