Definition of "wardroom"

There were only about a dozen officers in the great wardroom, six of them in the khaki gabardine working uniform of the U.S. Navy.

1957, Neville Shute, chapter 1, in On the Beach‎, New York: William Morrow & Co

[…] it having also reached the ears of the Ward-room that the work contained reflections somewhat derogatory to the dignity of the officers, the volume was seized by the master-at-arms, armed with a warrant from the Captain.

1850, Herman Melville, chapter 11, in White-Jacket‎, New York: Harper, published 1855, page 56