from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A floor beneath a main basement of a building.

from The Century Dictionary.

  • noun A basement lower than the main basement of a building. In the largest modern buildings there are sometimes three or four of these, one below another.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A basement located beneath another basement


from Wiktionary, Creative Commons Attribution/Share-Alike License

sub- +‎ basement


  • The building isn't without fault: The unexpected discovery of an underground wellspring early in the construction process forced Mr. Kahn to cancel plans for a subbasement and to build the library 1½ stories higher than planned, contributing to the bulky feel of the exterior.

    A Monument to the Life of the Mind

  • A video pre-confession from every bomber could still not explain why the subbasement was blown up ...

    9/11 Truth and the Paranoid Style - Boing Boing

  • For all the horrors you hear about Congress's poisoned atmosphere—its paralysis, its subbasement approval ratings—the handsome marble hallways, filled with American flags, still gleam; wide-eyed constituents still travel them; and it's still hard not to find yourself with something resembling a lump in your throat.

    A Pillar of Democracy

  • Julia was pretty sure the library didn't have any subbasement stacks, because it didn't have a subbasement.

    'The Magician King'

  • The call number was odd—it put the book in the subbasement stacks.

    'The Magician King'

  • These included the Manhattan Project and housing the 'Arsenal' robots in a hidden subbasement in his mansion.

    Kenneth Branagh Talks Thor | /Film

  • Three years after the crisis began with a burp in the subprime subbasement, these questions elicit scant consensus.

    Robert Teitelman: Transactions: Oct. 18, 2010

  • The dropping sensation in her stomach was just an ordinary dropping sensation, the kind you get when you're descending rapidly toward a subbasement full of cheap metal shelving and the buzz of fluorescent lights and exposed pipes with red-painted daisy-wheel valve handles poking out of them at odd angles.

    'The Magician King'

  • It reached high into the room, standing some four stories taller than the ground floor, and it fell away below their feet into a vastly deep subbasement.

    The Dragon’s Apprentice

  • Befitting our status, the CRs were in the subbasement, under the parking garage and next to the print shop.



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