I have recorded a brief explanation of Benjamin Graham's definition of an investment, from his book, The Intelligent Investor. Here's the definition:
"An investment operation is one which upon thorough analysis promises safety of principal and an adequate return."
Who was Benjamin Graham?
The greatest investment advisor of the twentieth century, Benjamin Graham was the author of two seminal books on investing: Security Analysis, the textbook for the investment industry, and The Intelligent Investor, the first book ever to describe, for individual investors, the emotional framework and analytical tools that are essential to financial success. Graham’s philosophy of “value investing” - which is to look for values with a significant margin of safety relative to prices – has made The Intelligent Investor the stock market bible ever since its original publication in 1949. His writings truly have an almost biblical feel to them, not only from the timeless wisdom in his words, but also in the poetic nature of his delivery.