It looks like this question may have already been answered. But just in case, I've got a definition from here: https://decryptionary.com/dictionary/market-capitalization/

"Market Capitalization is a way to rank and judge the size of a cryptocurrency or stock in a company. The total dollar value is calculated by taking the total supply and multiplying it 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." -Decryptionary