This document discusses the differences between investment, speculation, gambling, and arbitrage. Investment is characterized as having a long time horizon of over 12 months, limited risk, stable income from enterprise earnings, and cautious investors using their own funds. Speculation has a short time horizon under 12 months, high risk, uncertain income from price changes, and aggressive investors using both own and borrowed funds. Gambling involves risk for the sake of risk with no investment view. Arbitrage earns risk-free profits from temporary price differences in efficient markets.