das Deck
deck
The walkable, open upper surface of a ship.
Die Passagiere versammelten sich bei Sonnenuntergang an Deck.
The passengers gathered on deck at sunset.

deck
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deck
The walkable, open upper surface of a ship.
Die Passagiere versammelten sich bei Sonnenuntergang an Deck.
The passengers gathered on deck at sunset.

'Deck' is a loanword from English. Many of its meanings in German are derived directly from the English uses, for example on a ship or as a set of playing cards.
Für dieses Kartenspiel brauchen wir ein komplettes Deck mit 52 Karten.
For this card game, we need a complete deck with 52 cards.
In connection with ships, the fixed expression 'an Deck' is used without an article to describe both location and direction. You say 'an Deck sein' (to be on deck) and 'an Deck gehen' (to go on deck).
Komm, wir gehen an Deck, um die frische Meeresluft zu genießen.
Come on, let's go on deck to enjoy the fresh sea air.
When 'Deck' refers to a level or floor, the context is usually a parking garage ('Parkdeck', parking deck) or a vehicle such as a double-decker bus ('oberes Deck', upper deck).
Wir haben auf dem untersten Parkdeck keinen Platz mehr gefunden.
We didn't find any space left on the lowest parking level.
When it is about games, 'Deck' means a set of playing cards. Typical verbs in this context are 'mischen' (to shuffle), 'austeilen' (to deal), or 'abheben' (to cut the deck).
Wer mischt das Deck für die nächste Runde?
Who's shuffling the deck for the next round?
plain / level
'die Ebene' and 'das Deck' can both mean a level or floor. 'Ebene' is more general and fits buildings, plans, or technical structures. 'Deck' is used mainly for ships and sometimes for certain vehicles or facilities, for example in a parking garage or double-decker bus. The words can be confusing because both can refer to a walkable level. As a practical rule: when it is about a ship, 'Deck' sounds natural. When speaking generally about a level, 'Ebene' is usually more appropriate.

Im Parkhaus finden wir auf dem zweiten Deck noch einen freien Platz.
In the parking garage, we can still find a free space on the second level.
Die Kinderabteilung liegt auf der oberen Ebene des Kaufhauses.
The children's department is on the upper level of the department store.