The terms 'bull' and 'bear' are used in stock exchange, what are the aims of it?

A person who thinks a market (any market, not just the stock market) can be described as a bull.  Anybody who thinks it will go down is a bear.

The oil price is currently in a bear market.

The bull market is when prices goes up rapidly, which might lead to economic cycle, a full recession. the bear market is quite the opposite, it's when it declines.under 20% or more under two months.

The actual origins of these expressions are unclear. Here are two of the most frequent explanations given:

1. The terms "bear" and "bull" are thought to derive from the way in which each animal attacks its opponents. That is, a bull will thrust its horns up into the air, while a bear will swipe down. These actions were then related metaphorically to the movement of a market: if the trend was up, it was considered a bull market; if the trend was down, it was a bear market.
2. Historically, the middlemen in the sale of bearskins would sell skins they had yet to receive. As such, they would speculate on the future purchase price of these skins from the trappers, hoping they would drop. The trappers would profit from a spread - the difference between the cost price and the selling price. These middlemen became known as "bears", short for bearskin jobbers, and the term stuck for describing a downturn in the market. Conversely, because bears and bulls were widely considered to be opposites due to the once-popular blood sport of bull-and-bear fights, the term bull stands as the opposite of bears.

On Wall Street, the bulls and bears are in a constant struggle. If you haven't heard of these terms already, you undoubtedly will as you begin to invest.The Bulls A bull market is when everything in the economy is great, people are finding jobs, gross domestic product (GDP) is growing, and stocks are rising. Things are just plain rosy! Picking stocks during a bull market is easier because everything is going up. Bull markets cannot last forever though, and sometimes they can lead to dangerous situations if stocks become overvalued. If a person is optimistic and believes that stocks will go up, he or she is called a "bull" and is said to have a "bullish outlook". The Bears A bear market is when the economy is bad, recession is looming and stock prices are falling. Bear markets make it tough for investors to pick profitable stocks. One solution to this is to make money when stocks are falling using a technique called short selling. Another strategy is to wait on the sidelines until you feel that the bear market is nearing its end, only starting to buy in anticipation of a bull market. If a person is pessimistic, believing that stocks are going to drop, he or she is called a "bear" and said to have a "bearish outlook". 

it is give us idea what our decision sell or buy

Thanks

Agree with Colleague Ahmed Ahusaini and Mr, Duncan answers

I really have no idea about market and stock market, but the provided answers is really interested. Thanks to everyone. 

It's the buying/selling behavior of the buyers. Bullish is more aggressive whereas bearish is a suble, mild approach.

I fully agree with the answers been added by EXPERTS....THanks

Sorry, I don't have an answer

Bull market mean the rise of share value and Bear mean decline of the share value.