Word "Mat" shortened from Automatically
Was becoming big by the 1930's and 1940's.
Between the whole Streamline Moderne movement coupled with advances in electric appliances there were changes afoot. Many of them were geared towards making life easier and or better for those involved in housekeeping.
As founder of this wonderful website, and our dear Webmaster made clear doing laundry "automatically" was a dream come true for many.
While various conventional/wringer washers had been around since early part of 1900's, most still required some sort of user interaction. This meant while wash day was shortened from two or three days down to several hours, one still was tied down for that period. This was of course even if one could afford or had access to such devices. Well though the 1940's/1950's plenty were still doing washing with tubs, washboards and maybe hand cranked mangle.
Westinghouse had the "Laundromat", Bendix the "Economat", and on a side note you could get food at an "Automat", but the marketing was clear. One was freed from the often no small amount of time spent doing things like cooking, baking, the wash, etc...
Westinghouse, Bendix and other makers of automatic washing machines were quick to lay things on thick. Housewives and others could simply load dirty wash into machine, add soap/detergent, close things up, turn a dial/start machine and come back later to clean wash, all *Automatically*.
As the advert above for Laundryette made clear even if one had to go out to a "laundromat" the appeal was clear. Instead of the wash houses of old which still had one tied to tubs, washboards, etc... these "automatic" laundry places were a godsend. Washing could be done in thirty minutes instead of several hours with little human intervention involved aside from loading and unloading.