Definition of Flat
A place covered with water too shallow for navigation with vessels ordinarily used for commercial purposes. The space between high and low water mark along the edge of an arm of the sea, bay, tidal river, etc.
A floor or separate division of a floor, fitted for housekeeping and designed to be occupied by a single family. An apartment on one floor. A floor or story in a building. A building, the various floors of which are fitted up as flats, either residential or business.
In insurance, a policy without coinsurance provision; a provision for termination of renewal policy within short period after anniversary date without charge to insured.
In finance, stock is sold flat when no provision is made for adjusting accrued dividends.
That's the definition of Flat in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.