What constitutes a minor currency pair can vary depending on where you look. Some brokers stipulate that a minor pair can’t include the US dollar, for example, and as such refer to them as ‘crosses’.
More generally, a minor pair is any currency pair that’s traded less frequently than the majors, even if one or both constituent pairs also appear in a major currency pair. Some of the more popular include CHF/JPY, GBP/CAD and EUR/SGD.