My friend in PA worked in production shop that made Koret and other brands of clothes in the 1980's.
She called the large "serger type " machine a Marrow because she said it was the name of the manufacturer of it.
Naturally, it was industrial but later yrs she said my serger was similar. In 70' & 80's I don't think many of
us had small home sergers. Kind of like pc's --until they got processed for the masses