Market capitalization or Market Cap is defined as a way to rank the value and size of an asset (stock, cryptocurrency, etc.). This is calculated by multiplying the total number of coins by the latest price.
To get market cap, the total supply (of a stock or cryptocurrency) is multiplied by the price. For example, if bitcoin is worth $4,000 and there are 16,500,000 coins in existence, that means its market cap is $66,000,000,000 or 66 billion dollars.