a shallow box in which seedlings are started
"The gardener carefully transferred the delicate tomato seedlings from their flat into the main garden bed."
a musical notation indicating one half step lower than the note named
"The conductor raised his baton to signal that we should play the flat B instead of the sharp B in this measure."
scenery consisting of a wooden frame covered with painted canvas; part of a stage setting
"The crew spent all morning moving the heavy flat across the stage to set up for the final act."
An area of level ground.
"After moving out of our cramped house, we finally found a spacious flat in the city center that fit all our furniture comfortably."
Level ground in general.
An apartment, usually on one level and usually consisting of more than one room.
In plain English: A flat is an apartment that someone rents to live in.
"She decided to rent a small flat in the city center."
Usage: Use "flat" as a noun to refer to an apartment or self-contained housing unit that occupies the ground floor or one level of a building. This term is common in British English but is less frequently used in American English, where "apartment" is the standard equivalent.
To make a flat call; to call without raising.
"The boxer landed a flat punch that echoed loudly against his opponent's jaw."
To beat or strike; pound
In plain English: To flatten something means to press it down so it becomes smooth and level with no bumps.
"The tire went flat after hitting a large pothole."
Usage: Use the verb flat only in specific literary or dialectal contexts to mean striking something repeatedly with force, such as beating a drum or pounding on a door. In modern everyday English, it is far more common to use this word as an adjective describing a lack of sound, variation, or elevation rather than as an action.
not modified or restricted by reservations
"a categorical denial"
"a flat refusal"
lacking contrast or shading between tones
"The black-and-white photograph had a flat quality that made all the faces look like they were cut out of cardboard."
flattened laterally along the whole length (e.g., certain leafstalks or flatfishes)
"The flatfish swam along the sandy ocean floor, its body completely flattened laterally to blend in with the seabed."
lacking taste or flavor or tang
"a bland diet"
"insipid hospital food"
"flavorless supermarket tomatoes"
"vapid beer"
"vapid tea"
sounded or spoken in a tone unvarying in pitch
"the owl's faint monotonous hooting"
lacking the expected range or depth; not designed to give an illusion or depth
"a film with two-dimensional characters"
"a flat two-dimensional painting"
Having no variations in height.
"The newly paved road was so flat that we could see for miles without seeing any hills or valleys."
In a horizontal line or plane; not sloping.
"The surveyor adjusted the tripod until the bubble centered, confirming that the ground was perfectly flat."
In plain English: Flat means having no height, bumps, or curves so that everything on it is level and smooth.
Usage: Use "flat" to describe surfaces that are level and have no bumps or dips, such as a flat table or a flat roof. It specifically contrasts with uneven terrain where the height changes from point to point.
So as to be flat.
"She carefully pressed the dough into a thin, flat circle before placing it on the baking sheet."
In plain English: To do something flat means to perform it without any energy or enthusiasm.
"The tires went flat after hitting a large pothole."
Usage: Use "flat" as an adverb to mean directly or without any qualification, such as when someone speaks flatly or pays flat out. It modifies verbs to indicate that an action is done in a straightforward manner or at a fixed rate.
The word "flat" comes from Old Norse flatr, which itself traces back to a Proto-Indo-European root meaning "flat." This term entered Middle English as an adjective describing level ground or a smooth surface before eventually becoming the noun we use today.