A stock symbol, often referred to as a ticker symbol, is a unique series of letters or a combination of letters and numbers assigned to a publicly traded company's shares of stock. It serves as a shorthand representation for easy identification and tracking in the financial markets.

The concept of stock ticker symbols has a fascinating historical origin. In the early days of stock trading, communication was not as seamless as it is today. Investors and brokers needed a way to quickly convey information about stock prices without relying on lengthy company names. Enter the stock ticker.

The stock ticker was an electromechanical device that printed stock quotes on thin strips of paper. Each company's stock was associated with a unique set of letters that could be easily transmitted and understood. This set the stage for the birth of stock ticker symbols.

Fast forward to the present day, and stock ticker symbols have become integral to the language of finance. These symbols are typically a combination of letters, and in some cases, numbers. For instance, well-known companies like Apple Inc. is AAPL, Microsoft Corporation is MSFT, and Alphabet Inc. (the parent company of Google) is GOOGL.