a house that has two storeys in front and one storey at the back, with a gable roof that extends downwards over the rear
saltbox in American English
(ˈsɔltˌbɑks)
noun
1.
a box for salt, with a sloping lid
2. US
a house, as in colonial New England, shaped somewhat like this, having two stories in front and one at the rear, and a gable roof with a much longer slope at the rear