doubledeck

Doubledeck is a general term used to describe objects, vehicles, or structures that incorporate two parallel decks or levels. The term may appear as double-deck, double-decked, or doubledeck, and is often used as a descriptive label rather than a formal classification. The overarching idea is to increase capacity, storage, or functionality by stacking two layers above one another.

In transportation, the concept is widely employed. Double-decker buses and trains carry more passengers by adding a second level of seating without extending the vehicle length. Some ships and ferries use a two-deck arrangement to separate passenger areas from cargo or to provide multiple viewing levels for passengers.

In gaming and gambling, double-deck variants exist. Double-deck blackjack, for example, uses two standard decks of cards, with rules and house edge that differ from single-deck games.

In architecture and venue design, double-deck stands or galleries let spectators be seated on two elevated tiers, increasing seating capacity in arenas and stadiums.

Outside these uses, the term remains a generic descriptor for any two-tiered arrangement, and it often appears in product names or design briefs. See also double-decker, deck (nautical), and two-tier design.