Question: Is it "Tone Arm" or is it "Tonearm"?

I've seen it spelled both ways, (although mostly I've seen it as "Tonearm" in most Audiophile applications, which is how I typically write it). My Word program prefers it spelled "Tone Arm", when it comes to the spell check though.

What say you?

I did try to figure it out online, but it works both ways.
(See link below.)

List of definitions, both ways

And Google apparently has it as two words.

Interesting, huh?
Spell checkers may have made us soft, as they don't recognize many proper words. This probably led to the rise of Tone Arm. However, it's always been Tonearm.
Hey Kenny,

Now that I have started researching this, I am not so sure it has always been "Tonearm".
I am beginning to think it may have started as "Tone Arm", or possibly "Tone-Arm".

Check out this link discussing a phonograph from about a century ago.

1904 phonograph

I wish I could get copies of the patents, particularly those from the Victor Company, as it appears he may have truly invented the tone-arm, (or however you wish to spell it!!!) ;-)
Hey Bill, (Audiofeil)

I just happened to be checking out your website, and I saw the pictures you had of the Dynaudio Sapphire speakers you have for sale.

Dynaudio Sapphire

Wow, is all I can say. These are some of the most beautiful speakers I've ever seen. (Not that I can buy them, since I am in California, and you can't ship them - and I have no money anyway.) I've seen other pictures of them before, and while they look good, these look incredibly good. You called it an ivory finish, but it looks more like birds-eye maple in the photographs. More photographs would be appreciated!

Question: I've heard the Temptation speakers before. How do these compare to that?

FYI, I have no affiliation with Bill, or his company.
I just happened to notice these speakers, and since he was a contributer to this thread, I thought I would address him here.
Funny, I've always called it the "phono pic-up suspension mast/headshell assembly". Indecently, is it pic-up or pic up?

Hey, spellcheck does not recognize "phono" or "headshell"!
WTF? It doesn't think "spellcheck" is a word!?!
Hey Kurt,

Actually, it was not referred to as a Tone Arm back then, so this was the writers' modern interpretation. In the Victrola Owner's Manual this was referred to as the Taper Tube and Sound Box. See:
Hey Kenny,

Cool website.

I find this one page particularly interesting.

The tonearm/tone arm/tone-arm Page

In one paragraph, they refer to the "subject of our discussion" as:
Tone arm

Covering all the bases there, huh?!

I am getting the feeling that there is no correct answer to my question, and it is merely up to the writer to decide which version they prefer. (Although it does appear that over time, tonearm has become the preferred choice.)
My wife is an Editor of thirty five years. Her reference is Merriam-Webster's Collegiate Dictionary (The Book). The definition is:

Tonearm: the movable part of a phonograph or record player that carries the pickup and permits the needle to follow the record groove.

Thank goodness for simplicity and the classically educated!
Strictly speaking, it's a pickup arm. Having said that, I call them tonearms so people know what I'm talking about.

When in Rome ...

Thom @ Galibier