gap, spread -- (a conspicuous disparity or difference as between two figures; "gap between income and outgo"; "the spread between lending and borrowing costs")
opening, gap -- (an open or empty space in or between things; "there was a small opening between the trees"; "the explosion made a gap in the wall")
gap, crack -- (a narrow opening; "he opened the window a crack")
gap -- (a difference (especially an unfortunate difference) between two opinions or two views or two situations)
break, interruption, disruption, gap -- (an act of delaying or interrupting the continuity; "it was presented without commercial breaks"; "there was a gap in his account")