Volume refers to how much of a cryptocurrency or crypto asset has been traded within a specified amount of time.
The most common time frame recorded is the 2h-hr volume of an asset or a market in general. Volume simply depicts the total number of buying and selling executed on a particular market for a specified time frame.
The volume of an asset is beneficial to many traders as it can provide insights into predicting short-term and long-term price movement, and it can be reported in traditional stocks, fiat currencies, or cryptocurrencies. For instance, if trader A is willing to sell 2.5BTC to trader B at a price of $50,000, the trade volume can either be written in USD (i.e. $125,000) or simply as 2.5BTC if the trade is conducted successfully. Either way, the volume may be reported, it will be added to the trading activities of other trades within the calculated time frame.
Volume may be useful in determining the strength of a trending market. In a situation where a relatively high volume backs the upward/downward movement in the price of an asset, then the market trend is considered viable. However, if the movement in price is backed by a low volume, traders will usually look to other trading tools to inform trading decisions.
Although experienced traders may almost never make market decisions based on the volume of an asset alone, it is still one of the fundamental factors considered by many to support their trading speculations.