At the bottom of the stock chart, you'll find a bar graph that represents the number of people who purchased stocks of the company over a period of time. If you find that more people were interested in the stocks when the prices were up, then it is a healthy trend and in stock market terminology, is referred to as bullish (bull signifies an investor who is of the opinion that the market will witness further growth). However, if the number of interested people decrease with the increase in the price of stocks, then the trend is termed as bearish (bear signifies an investor who thinks that the market will witness decline) and it is not advisable to invest in stocks that exhibit bearish trends.