The term steaming light has been substituted many times to try to
eliminate the confusion
associated with the "mast-head" light.


Although I see what you're getting at here, I'm going to disagree a bit.
"Masthead" refers to the arc of visibility more than it's location (on
the mast-top or forward portion of the mast) since it can be located on
top of a mast, pole ....
You are correct, in that an "all-around" light should not be called a
"masthead", but it's because of it's 360 deg arc of visibility.
It's also possible to refer to that portion of the arc of a 360 deg
light which encompasses 225 deg (rt ahead to 2 pts abaft, either side)
as the "masthead" portion of that light.
The "steaming" light refers to the masthead light, but in some boats it
can also refer to the 360 deg light.

I believe that in Canada for a boat under 12m(?) that the steaming light and
stern light must separate lights but for boats under 12 m there can be a
single 360 degree light. This has resulted in many power boats being built
with a 360 degree anchor light at the top of the metal mast and a steaming
light on the front side of the mast and a stern light on the rear side just
below it. I do not believe that the lower two would appear any different the
single anchor light from a distance but one is legal and one is not.

RW