(n) a suite of rooms usually on one floor of an apartment house
(n) scenery consisting of a wooden frame covered with painted canvas; part of a stage setting
(n) a deflated pneumatic tire
(n) a shallow box in which seedlings are started
(n) freight car without permanent sides or roof
(n) a musical notation indicating one half step lower than the note named
(n) a level tract of land
(s) lacking variety in shading; "a flat unshaded painting"
(s) not reflecting light; not glossy; "flat wall paint"; "a photograph with a matte finish"
(s) (of a tire) completely or partially deflated
(s) having no depth or thickness
(s) 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"
(s) having a horizontal surface in which no part is higher or lower than another; "a flat desk"; "acres of level farmland"; "a plane surface"
(a) lacking contrast or shading between tones
(s) without pleats
(s) parallel to the ground; "a flat roof"
(s) stretched out and lying at full length along the ground; "found himself lying flat on the floor"
(s) not made with leavening; "most flat breads are made from unleavened dough"
(a) lowered in pitch by one chromatic semitone; "B flat"
(s) not increasing as the amount taxed increases
(s) not modified or restricted by reservations; "a categorical denial"; "a flat refusal"
(s) having lost effervescence; "flat beer"; "a flat cola"
(s) lacking stimulating characteristics; uninteresting; "a bland little drama"; "a flat joke"
(s) lacking taste or flavor or tang; "a bland diet"; "insipid hospital food"; "flavorless supermarket tomatoes"; "vapid beer"; "vapid tea"
(s) flattened laterally along the whole length (e.g., certain leafstalks or flatfishes)
(r) wholly or completely; "He is flat broke"
(r) in a forthright manner; candidly or frankly; "he didn't answer directly"; "told me straight out"; "came out flat for less work and more pay"
(r) at full length; "he fell flat on his face"
(r) against a flat surface; "he lay flat on his back"
(r) below the proper pitch; "she sang flat last night"
(r) with flat sails; "sail flat against the wind"