$BTC When you see "$btc" in the context of a "currency pair" on "Binance", it almost certainly refers to Bitcoin (BTC) as the base currency in a trading pair. Binance is a leading cryptocurrency exchange where you can trade various digital assets.

Here is a brief note on what it means:

* Currency Pair: In cryptocurrency trading, a currency pair represents the exchange rate between two different cryptocurrencies. It is always displayed as "Base Currency/Quote Currency." For example, BTC/USDT means you are trading Bitcoin (BTC) against Tether (USDT). Effectively, you are saying how much USDT is needed to buy one BTC, or how much USDT you get when selling one BTC.

* BTC as Base Currency: When BTC is the first currency in the pair (for example, BTC/USDT, BTC/ETH, BTC/BNB), it is the "base currency." This means you are buying or selling BTC using the second currency (the "quote currency").

* "Short Selling" BTC on Binance: Short selling (or shorting) is a trading strategy where you profit from a decrease in the price of an asset. On Binance, you can short BTC mainly through:

* Margin Trading: You borrow BTC from Binance, sell it at the current market price, and then buy it back later at a lower price to return the borrowed BTC (plus interest), benefiting from the difference.

* Futures Trading (for example, BTCUSDT Perpetual Futures): This involves trading derivative contracts that speculate on the future price of BTC. You can take a "short" position on a futures contract, betting that the price of BTC will fall. Perpetual futures have no expiration date and use a "funding rate" mechanism to keep their price close to the spot price.

Essentially, "$btc on Binance" as a currency pair implies trading Bitcoin against another asset on the Binance exchange, and "shorting it" means you expect the price of Bitcoin to decrease.