I recall growing up in New Hampshire during the 1960's that it was a very commonly used expression especially among some of my friends in high school and so an example of how the the word daow might be used would be in response to a question when the answer would be a no but one perhaps wanted to add a bit of color to one's response so if someone were to ask me whether I caught any fish yesterday, my response might be daow suggesting of course that I hadn't and of course I hadn't and again making it a little bit more humorous than just a plain no. 

The geographic area for which this expression is is used and certainly has been used for many many generations corresponds rather closely to a particular way that building roofs have been constructed over time and so specifically it's looking at whether on a building roof the roof boards were laid horizontally or vertically. 

In eastern New England, and I would say from from the Boston area along the Maine coast, east to New Hampshire into eastern Vermont, prior to the 1840s, it was common to have roof boards laid vertically from the ridge to the eaves supported by horizontal timbers that we call purlins. What I love about my work here at the University of Vermont in the historic preservation program is the ability to work closely with so many people across the region and by doing research and engaging with a broad range of people, we're able to get a better understanding not only of the past, but also of where we are today.