What is the US equivalent of coronet 10 tex yarn?

I have a pattern that originated in eastern Europe and the yarn weights are listed as coronet 10 tex, 12 tex, and 50 tex. I have NO IDEA what this means in US terms. I'm looking for something like "lace weight" or "sport weight" or even a number 1-6 (ultra fine to super bulky). I have a feeling the smaller may be lace weight yarn, but I can't find a proper conversion online.