Final answer:
A bull market is characterized by investor optimism, an upward trend in stock prices, and overall confidence in the financial market's prospects.
Step-by-step explanation:
A bull market is characterized by investor optimism, which is usually accompanied by an upward trend in stock prices and general confidence in the financial markets. This is the time when investors believe that the upward trend in the stock market will continue in the long term and are more likely to invest in hopes of achieving profits. Contrarily, a bear market, its opposite, is defined by falling stock prices and generally prevails during economic downturns or periods of pessimism among investors.