structures and equipment placed on a supporting structure (fixed or floating) to provide some or all of a platform’s functions
Note 1 to entry: For a ship-shaped floating structure, the deck is not part of the topsides.
Note 2 to entry: For a jack-up, the hull is not part of the topsides.
Note 3 to entry: A separate fabricated deck or module support frame is part of the topsides.
Source: ISO 19900:2013, Petroleum and natural gas industries – General requirements for offshore structures. Global Standards