main deck

the uppermost weatherproof deck, running the full length of a ship.

Origin of main deck

First recorded in 1740–50

A word formerly used in our ships for "get ready;" as, "Predy the main-deck," or get it clear.

The Sailor's Word-Book |William Henry Smyth
There are eight 8-inch guns on the superstructure, in sets of twos, and amidships on the main-deck are four 6-inch rifles.

Pike & Cutlass |George Gibbs
I looked and found it had been an illusion of my sight, due to the flame of the flare that was burning fiercely on the main-deck.

My Danish Sweetheart., Volume 1 of 3 |William Clark Russell
The deck immediately below this once-divided deck is always called the main-deck.

How Britannia Came to Rule the Waves |W.H.G. Kingston

The beams of the main-deck are of American or German oak, those of the lower deck and half-deck of pitch-pine and Norwegian fir.

The South Pole, Volumes 1 and 2 |Roald Amundsen

main deck

the uppermost sheltered deck that runs the entire length of a vessel