The quote currency is the currency that is used as a reference. It is always the second currency quoted in a currency pair (i.e. base/quote or ETH/BTRN). On this page, the quote currency is Biotron (BTRN).The price of a trading pair is always displayed in the quote currency.
On cryptocurrency exchanges, the quote currency is almost always Bitcoin, Ethereum, a fiat/governmental currency, or a stablecoin (such as Tether or USDC). The quote currency is often referred to as the "secondary currency" or "counter currency."
Because traders are concurrently selling and buying cryptoassets, quotes are displayed in pairs. For example, when an investor trades across the ETH/BTC pair, they are -- at the exact same moment -- buying Ethereum and selling Bitcoin (or buying Bitcoin and selling Ethereum).