Sl st crochet meaning refers to slip stitch, written with a space between the abbreviated letters by some designers and without a space by others. I use slip stitch constantly to join rounds and move across stitches without adding fabric height. This guide gives the direct definition.

Direct Answer
Sl st stands for slip stitch, worked by inserting the hook, yarning over, and pulling through both the stitch and the loop on the hook in one motion, adding no height to the fabric.

Frequently asked questions
When is slip stitch used in a pattern?
Slip stitch is commonly used to join a round, move across several stitches invisibly, or create a very flat, low-profile edge finish.
Want more abbreviations explained?
See the full symbol and abbreviation reference guide.
See the abbreviations guide