Market capitalisation (market cap) is calculated as current price multiplied by circulating supply, giving a rough sense of an asset's total market size. It's widely used to rank and compare cryptoassets, similar to how it's used for public companies.
Market cap has real limitations worth knowing: it can be manipulated by projects with low liquidity, and it doesn't tell you anything about how much real trading volume, usage, or liquidity actually backs that number. A large market cap on paper doesn't automatically mean you could sell a large position without moving the price significantly.