[Leica] LTM?

[john <bosjohn@mediaone.net>]

I have noticed that many here refer to older Leica cameras and lenses as LTM
(Leica thread Mount).  I have not come across this expression much in all my
years of Leica use until quite recently . We always called them screw mounts
when I was a callow youth back in the fifties.  I was curious so I checked a
couple of my books to see what they call them. Denis Laney seems to refer to
them as screw mounts as does my Leica Manual 15th Edition edited by Douglas O.
Morgan, David Vestal, and William L Broecker. I also find my Accessory Guide
from Hove Foto refers to screw mount items. I am wondering where this new
expression comes from. My late father, bless his collectors heart, thought it
was a collectors affectation, but this is a user group the use of this
expression seems widespread here as well as among collectors. What is the
etymology of this expression, and is it a more accurate description or is it
just changing custom? Will I be considered old fashioned if I continue to say
screw mount?
Bosjohn (John Shick)