A cross currency pair (or "cross") is any pair traded without the US dollar as either the base or quote currency, such as EUR/GBP or AUD/JPY. Its rate is effectively derived from each currency's dollar rate, even though the dollar never appears in the quote itself.
Crosses typically carry wider spreads than USD majors because liquidity providers price them by combining two dollar legs internally.
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How to Check the Way a Currency Is Managed
The regime behind a currency is published, not inferred. The four primary sources that say how a rate is governed, what each one can and cannot tell you, and how to keep the answer from going stale.