flat

a suite of rooms usually on one floor of an apartment house
scenery consisting of a wooden frame covered with painted canvas
part of a stage setting
a deflated pneumatic tire
a shallow box in which seedlings are started
freight car without permanent sides or roof
a musical notation indicating one half step lower than the note named
a level tract of land
lacking variety in shading

not reflecting light
not glossy

(of a tire) completely or partially deflated
having no depth or thickness
lacking the expected range or depth
not designed to give an illusion or depth

having a horizontal surface in which no part is higher or lower than another

lacking contrast or shading between tones
without pleats
parallel to the ground

stretched out and lying at full length along the ground

not made with leavening

lowered in pitch by one chromatic semitone

not increasing as the amount taxed increases
not modified or restricted by reservations

having lost effervescence

lacking stimulating characteristics
uninteresting

lacking taste or flavor or tang

flattened laterally along the whole length (e.g., certain leafstalks or flatfishes)
wholly or completely

in a forthright manner
candidly or frankly

at full length

against a flat surface

below the proper pitch

with flat sails