Usually, this means knitting two stitches, then passing the first stitch over the second, repeating for the number of stitches required.
Insert your needle into the edge of the sweater (often in the gap between stitches), wrap the yarn, and pull it through to create a new stitch. bost up
If you can share the rest of the line (e.g., "BO 2 sts, k3..."), I can tell you exactly what that row is supposed to do. Baby Knits From Around The World | PDF - Scribd Usually, this means knitting two stitches, then passing
To join, take the last stitch you worked (the edging stitch) and pass it over the newly picked-up stitch to securely connect a new section (like a border or sleeve) to the main piece. Baby Knits From Around The World | PDF
Based on the search results, "bo st up" appears to be a knit stitch abbreviation or a fragment of a knitting pattern, specifically a "Baby Knits from Around the World" pattern involving "BO" (Bind Off) and "st" (stitch) or "pick up" a stitch. "BO" (Bind Off) and "Pick Up" Guide
This sequence is often used for creating buttonholes or adding a border to a garment.