I. (ˌ)täp-ˈga-lənt, tə-ˈga- adjective
Etymology: top (I) + gallant (II)
Date: 1514
: of, relating to, or being a part next above the topmast and below the royal mast
topgallant sails
the topgallant mast
II. noun
Date: 1581
1. archaic : the topmost point : summit
the high topgallant of my joy — Shakespeare
2. : a topgallant mast or sail