In Ben Graham’s book, The Intelligent Investor, Graham discussed “Investment versus Speculation: Results to Be Expected by the Intelligent Investor.” He explained:

What do we mean by “investor”? Throughout this book the term will be used in contradistinction to “speculator.” As far back as 1934, in our textbook Security Analysis, we attempted a precise formulation of the difference between the two, as follows: “An investment operation is one which, upon thorough analysis promises safety of principal and an adequate return. Operations not meeting these requirements are speculative.”