An exchange rate is the price of one currency in terms of another. EUR/USD is how many US dollars one euro buys; EUR/GBP is how many pounds. These are the ECB's daily reference rates.
What moves them
Interest-rate differences — money tends to flow toward higher-yielding currencies.
Relative growth and inflation prospects.
Risk sentiment — in turmoil the dollar often strengthens as a safe haven.
Internal vs external value
Inflation measures the euro's internal value (what it buys at home); the exchange rate is its external value (what it buys abroad). A currency can hold up against peers while still losing purchasing power at home if those peers are inflating too. Both views matter when judging the health of the euro.
Source: ECB reference exchange rates, daily.