Volumes in the stock market are the number of shares that are being traded in the market. Here, the word ‘traded’ means the number of shares being bought and sold by the market participants at a particular point in time.

Source: in.tradingview.com

For example, we have taken the Bharti Airtel share chart where you can see that in September, the volume of the share started increasing now why it started increasing is a whole different topic called fundamental analysis of a company, let's not go there but here the bid & ask price is matching for the buyer and the seller continuously or you can say frequently for that particular period which increases volumes in numbers which subsequently helped the price of the stock move.

So, there is a relation between the price of the stock and the volume of shares being traded, if the price of the share is increasing and volume is also increasing along with it (Bullish move), if the price of the share is increasing and the volume is not increasing subsequently (trap) that means prices may fall in the next few trading sessions. if the prices are decreasing and the volume is increasing (Bearish move), and finally if the prices and the volume both are decreasing the prices may increase or go sideways depending on the current scenario.

Traders use average volumes which means if the average volume of the past 10 days of a stock is greater than the present-day volume, they anticipate that the price may rise and vice versa.