(adjective)
even in terrain, for example lacking waves, hills, or mountains, used to describe calm waters or an area of land;
e.g. They drove through the countryside, passing miles of flat land as they went.
(adjective)
lifeless or dull, lacking in energy, emotion, or enthusiasm, used to describe a person or their attitude;
e.g. She spoke in a flat voice because she was tired from the day's exertions.
(adjective)
sluggish or monotonous, lacking in activity or contrast/variation;
e.g. The market for new automobiles had become flat because of the economic recession. The walls were all painted a flat shade of beige.
(adjective)
having lost some or all of the air in something, for example lacking effervescence, used to describe a once-fizzy drink, or underinflated, used to describe a tire;
e.g. The soda had gone flat from being in the glass all day. Her car had a flat tire, so she took the bus to work instead.
(adjective)
constant and unvarying, remaining the same regardless of changing conditions or particular circumstances, used to describe a price, fee, or wage;
e.g. If you pay the flat parking fee, you can park your car here for anything between one hour and one day.
(adjective)
firm and absolute, direct and definitive, typically used to describe some communication such as a contradiction, a denial, or a refusal;
e.g. He gave a flat denial that he had been there, but we knew he was not telling the truth.
(adjective)
having a lower pitch than normal, or characterized by such lower-pitched notes, used to describe musical notes or a section of music;
e.g. I think that note was flat and out of tune.
(adverb)
in/into a horizontal/reclining position, or closely against something;
e.g. They had the map spread flat on the table.
(adverb)
in a lower pitch than normal or correct, used to describe the sound of a musical note;
e.g. She is playing the violin flat, and most of the notes are incorrect.
(adverb)
in informal usage absolutely or completely;
e.g. He expected them to flat refuse his request so he was surprised when they didn't.
(adverb)
in informal usage, used to emphasize how quickly something is done, in combination of an expression of time;
e.g. I'll run my errand and be home in fifteen minutes flat.
(noun)
the portion of something that has a smooth, level, horizontal surface;
e.g. The flat of the pot prevents it from rolling when it is set down.
(noun)
a shoe that has a very low heel or no heel at all (usually used as "flats" to refer to a pair of such shoes);
e.g. She wore a pair of flats so that she could walk around easily.
(noun)
a piece of scenery that is used on a stage in a play (or some other such performance) and that is mounted on a movable frame;
e.g. Part of the stage was occupied by a flat depicting the front of a large house.
(noun)
in informal American usage, a tire of a vehicle that is low on air (i.e. deflated), usually due to a puncture;
e.g. He only noticed that his bike had a flat when he was getting ready to leave.
(noun)
a musical note that is lower than its natural pitch by a fixed interval (a semitone), or the symbol appended to a musical note to indicate this in writing;
e.g. The singer sang a flat by mistake, which sounded odd and jarring in the middle of the song.
(noun)
in British usage, a set of rooms on the same floor that make up a single residence, especially when such a unit is located in a large building containing several other such units, i.e. an apartment;
e.g. He rented a flat in the middle of the city, close to his office.
(verb)
in old usage, to make something level or horizontal (i.e. to make something flat);
e.g. Use a rolling pin to flat the dough into a sheet.
