Clarification needed with yarn and thread

[Nubs]

I have this Normandy Linen which is wet spun linen (16/2, 16/4, 40/2). It comes unwaxed but I have been able to wax it nicely to prevent fraying and untwisting. 

 

I know thread is two or more tightly twisted yarn but at what point does yarn truly become thread? I see 3 ply thread, and I see 3 ply yarn. How tight does thread have to be? My apologies if this is going right over my head but why couldn't you just use 2 or 3 ply waxed yarn if it was thin enough for leather work?

 

I think some sites call this yarn but it reminds me of unwaxed twisted polyester thread. Could I realistically use it for hand stitching? I feel like I could.

 

I wish every country would just follow 1 way of measuring fibers, yarns, threads and fabrics. 

[Bert51]

I believe you are check with that statement, but sadly some people in some countries believe they are using the correct measurement of not only thread but lots of things, why.

It would make our lives a little easier.

Buggar, Little People in Little Offices.

Off soapbox, for now.

Bert.