The lowest deck of a ship, especially a warship, having at least four decks.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "orlop" in a sentence
"Below this again is one still lower-deck called the orlop-deck."
"The "orlop" or eighth deck is devoted entirely to machinery with coal bunkers on each side of the boilers to provide against the effect of collisions."
""Battered chain-gangs of the orlop, grizzled draughts of years gone by ...""