Definition of "flatiron"

A simple iron (for pressing laundry) which is heated on a stove.  examples

A pair of metal tongs with heated ceramic plates used for straightening hair.  examples

(especially referring to the shape of a building) a quadrilateral with two parallel sides, one of which is very short, and whose non-parallel sides are longer than either parallel side.  examples

(geomorphology) A steeply sloping triangular landform created by the differential erosion of a steeply dipping, erosion-resistant layer of rock overlying softer strata.

Ellipsis of flat iron steak.  examples

Having a flatiron shape.  quotations  examples