Amateur radio (ham radio) morse code abbreviation for wife.
Hams call any (assumed) single
female ham radio operator a YL or "young lady". A ham radio operator's wife is often called an XYL or "ex-young lady" even if she is a
ham. Male operators are always called
OM or "old man". There is an obvious
double standard for women.
It's impossible to tell whether a person sending morse code is a man or a woman. Still, it was the custom for a long time to greet any operator on morse code as OM. Thankfully that custom is dying out. Now no
gender assumption is made.
Some women ham radio operators find XYL offensive. These operators prefer that hams refer to all women as YLs. The term XYL is still used frequently on the
air however. Perhaps this is because the vast majority of ham radio operators are men and apathetic about the feelings of women operators.
I agree with women operators that advocate for the universal use of YL especially since it is no longer customary to greet every
ham on morse with OM. The universal use of YL also removes a double standard.