: a large boreal gull (Larus hyperboreus) that is pure white with a bluish mantle when adult — called also burgomaster
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a large white and pale-gray gull, Latus hyperboreus, of Arctic regions.
[1820-30]
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glaucous gull,
a large white gull with a bluish mantle, of circumpolar oceans; burgomaster.
Useful english dictionary. 2012.