Bost Up -

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

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 bost up

This sequence is often used for creating buttonholes or adding a border to a garment. Based on the search results, "bo st up"