A few things you may not have known:

[ratchiweenie]

57. Where did the word Threshhold come from? in the 1500's

The floor was dirt. Only the wealthy had something other than dirt, hence the saying "dirt poor." The wealthy had slate floors that would get slippery in the winter when wet, so they spread thresh on the floor to help keep their footing. As the winter wore on, they kept adding more thresh until when you opened the door it would all start slipping outside. A piece of wood was placed in the entry way--hence, a "thresh hold."