Insigna of a French Vice-amiral d'escadre.
Squadron vice-admiral is an Anglicisation of a naval rank found in some navies of the world. The squadron vice-admiral, which could also be accurately translated as fleet vice-admiral, leads a squadron and is typically senior to a vice-admiral and junior to an admiral.
This anglicisation is not often used in practice, as the rank is usually kept in the original language or rendered as Vice-Admiral. The main navy to use the rank of squadron vice-admiral is the French Navy (vice-amiral d'escadre), where it is a four-star rank with a NATO code of OF-8, equivalent to corps general or lieutenant general in seniority. Officially, it is not a rank, but a style and position (rang et appelation in French) bestowed upon some vice-admiral (which is the actual highest substantive rank and is a three-star rank with NATO code OF-7 equivalent to rear admiral (upper half) or major general).
The original article can be found at Squadron vice-admiral and the edit history here.