a roof whose lower part slopes more steeply than its upper part (mansarde, from François Mansard (1598-1666), French architect)
{i} type of roof having two slopes on either side (lower slope is steeper than the upper one); room or story beneath a mansard roof
a hip roof having two slopes on each side (of a roof) having two slopes on all sides with the lower slope steeper than the upper; "the story formed by a mansard roof is usually called the garret