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!!!) ;-)
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!!!) ;-)