This is the 2698th most frequent Polish word.
dachem
"Dachem" is the instrumental form of "dach," meaning "roof" in English.
Here, 'dachem' is used in the instrumental case to describe movement under the 'roof' for protection from rain.
Idziemy pod dachem, ponieważ pada deszcz.
We are walking under the roof because it is raining.
In this instance, 'dachem' is used in the instrumental case to ascribe an attribute to the house.
Dom z dachem koloru czerwonego wygląda bardzo malowniczo.
The house with a red-colored roof looks very picturesque.
'Dachem' refers to being underneath the roof, showing a relation of location with respect to the roof.