I believe it means Extra Fine.
EF is the correct term.
Language laziness has to do with it mostly.
The X being used as in lets say, clothes sizes.
XL meaning extra large etc.
If there is a shortcut to either writing or speaking
then someone will coin it. I believe this all started
with our learned government and passed on to the military
with using acronyms. It spread from there. Now more than ever they are used.
Many are used on this site as well as in the numismatic world. Anyone outside of this world (like maybe mars etc:)
would have no clue of what some of the acronyms actually
stand for. As far as their use, don't get me started.

Note: RPM means revolution per minute
RPMM should be the correct term for the other RPM
I'm sure that a " DDR" (Duh, Dur) would get "Mad" though.
EF is the correct term.
Language laziness has to do with it mostly.
The X being used as in lets say, clothes sizes.
XL meaning extra large etc.
If there is a shortcut to either writing or speaking
then someone will coin it. I believe this all started
with our learned government and passed on to the military
with using acronyms. It spread from there. Now more than ever they are used.
Many are used on this site as well as in the numismatic world. Anyone outside of this world (like maybe mars etc:)
would have no clue of what some of the acronyms actually
stand for. As far as their use, don't get me started.
Note: RPM means revolution per minute
RPMM should be the correct term for the other RPM
I'm sure that a " DDR" (Duh, Dur) would get "Mad" though.






















