EUR/CHF is a currency pair, one of the "euro crosses". The two currencies are the euro (EUR) and the Swiss franc (CHF) from Switzerland.
As Switzerland is considered a safe haven, worries about the eurozone tends to make the CHF appreciate. If the CHF gets more expensive against the euro, this can become a problem for the Swiss export economy.
In such a situation, the central bank of Switzerland might decide to opt for a more active monetary policy such as changing the interest rate, creating opportunities for forex traders.