There is another explanation for “ Threshold”
When threshing corn in the threshing barn,a through draught would blow from the doors open at both ends.
The corn was flailed by hand , and the through draught blew away some of the chaff .
The threshold was literally that, a piece of wood just as described, was placed across the doorway to keep the corn seeds in as they were heavy by comparison with the chaff which would blow away.
It was to hold “ the thresh” in the barn.
Winnowing was allowing a breeze to blow through to leave the threshed corn but blow away much chaff. The corn was often tossed in the air and chaff blew away but seeds fell to the floor.
You can imagine it would also be used in the doorway of houses to keep,the strewn rushes on the floor in.
Which came first I do not know.
Rushes were the most commonly used floor covering.
Viktoria.
