What does tbl mean in knitting instructions?

Answer 1

It means "through back leg." When you look at a stitch on a knitting needle, imagine it is a cowboy sitting on a horse and the tip of the needle is the horse's nose. One leg is closer to you, and one is further away. For most knitters (in the U.S. and western Europe), it is the cowboy's right, or front leg that is leading, and the leg on the other side of the needle (back leg) is closer to the horse's tail than the front leg. It is important to notice whether your cowboy is sitting this way because it will effect the result of the tbl maneuver if he isn't. Usually (in the U.S. and Western Europe) you insert the needle into the front leg when knitting. This produces a normal stitch. If you insert the needle through the back loop, it will produce a twisted stitch. This is sometimes used for decoration, or for tightening an area that tends to be loose. Hold the needles nose-to-nose and insert the right needle into the stitch that way. That will put you through the back leg and produce the twisted stitch.

Answer 2

Through back loop