I. ˈtäp-ˈsīd noun
Date: 1815
1. plural : the top portion of the outer surface of a ship on each side above the waterline
2. : the highest level of authority
3. : the upper portion of the ionosphere
II. adverb or adjective
Date: 1873
1. : to or on the top or surface
2. : in a position of authority
3. : on deck