first floor

the ground floor of a building.

the floor above the ground floor of a building.

Origin of first floor

First recorded in 1655–65

Now, some of the kindergarten children were standing straight as soldiers in a line at the door of their first-floor classroom.

Freedom From Fear for Dreamer Kids |Mike Barnicle |November 24, 2014 |DAILY BEAST
In particular, Skylar had been caught frequently sneaking out of her first-floor bedroom window at night.

West Virginia Heathers: Was Skylar Neese Murdered by Her Best Friends? |Caroline Linton |December 19, 2013 |DAILY BEAST
He commenced firing down on people having their breakfast in the first-floor cafeteria.

Inside the Washington Navy Yard’s Building 197 During Alexis’s Rampage |Michael Daly |September 19, 2013 |DAILY BEAST
According to a 2008 Boston Globe profile of Romney, four portraits hang in the first-floor hallway of his house in Belmont, Mass.

Mitt Romney’s British Mormon Ancestors |Mike Giglio |January 31, 2012 |DAILY BEAST

Inside a first-floor chapel, the floor was stained with the blood of victims whose bodies were dragged into the building.

Egypt's Church Bombing: Was Al Qaeda Responsible? |Liam Stack |January 2, 2011 |DAILY BEAST
On the first-floor landing they were met by a truly ridiculous spectacle.

News from the Duchy |Sir Arthur Thomas Quiller-Couch
In the first-floor front room is a fine original ceiling in stucco, in which are the arms of Sir Paul Pindar.

Club Life of London, Volume II (of 2) |John Timbs
She has taken my first-floor apartments, with excellent references; and she gives remarkably little trouble.

Little Novels |Wilkie Collins
On the first-floor balcony men appeared dragging a great board faced with paper, on the paper enormous lettering.

If Winter Comes |A.S.M. Hutchinson
Deep paneled window seats, very common in contemporary houses, are a feature of the first-floor rooms.

The Colonial Architecture of Philadelphia |Frank Cousins

first floor

British the floor or storey of a building immediately above the ground floor US and Canadian term: second floor

US and Canadian another term for ground floor