what is "bobbin" thread ?

Bobbin thread is used for embroidery, a thinner, cheaper thread for the underside, where the tension is set so that the top thread is pulled slightly to the back. I would not use bobbin thread for regular sewing, although I could see using it top and bottom for very light lingerie or lace application.

thanks for reply,

i am no longer confused . i thought it was very fine then i noticed it says

i was thinking it might be useful for blind hems in a pinch ??? but i suppose one should just use the appropriate color/weight/composition thread for blind hems ? yes/no/maybe ?

thanks aga> > and why/what to use it for ?

It would be handy for blind hem in medium to light weight fabrics. Color matching is also good, but done well, the hemming will be invisible. It's just a bit tricky to be that good at it. Many people here are, I'm just not one of them. ;-)

Yes. At least for me, matching thread color to fabric is a

Beverly