The overall sentiment or feeling that the market is experiencing at any particular time. Greed, fear, expectations and circumstances are all factors that contribute to the group's overall investing mentality or sentiment.

While conventional financial theory describes situations in which all the players in the market behave rationally, not accounting for the emotional aspect of the market can sometimes lead to unexpected outcomes that can't be predicted by simply looking at the fundamentals.

Technical analysts use trends, patterns and other indicators to assess the market's current psychological state in order to predict whether the market is heading in an upward or downward direction.