mizzen topgallant
/ˌmɪzn tɒpˈɡalnt/ /ˌmɪzn təˈɡalnt/Nautical
noun
A topgallant situated just above the head of the mizzen-topmast. Chiefly attributive, especially in mizzen topgallant mast noun the mast above the mizzen-topmast.
Origin
Late 17th century; earliest use found in MSS House of Lords. From mizzen + topgallant.