To save space and to make them easier to read, patterns use a (mostly) standardized set of abbreviations. However, each designer may have “quirks” in their pattern based on regional differences or even symbols and abbreviations they created if they didn’t know another one.
Most patterns will contain a glossary or key that tells you what the abbreviations in that pattern are for, as well as to describe special stitches specific to that pattern. If you are confused, be sure to refer to a pattern’s glossary first. If you are still stumped, check the following standardized abbreviations: http://www.craftyarncouncil.com/knit.html
Helpful components of some patterns may also include:
Schematic: a line drawing that shows what finished dimensions of the pattern will be
Charts: used most often for colour work, lace, or cables. Charts can be very helpful in “visualizing” the way the work should proceed, but sometimes all those little symbols can look like alien hieroglyphs. Always check the pattern’s Chart Key first, as not all designers use symbols in the same way. However, the standardized symbols from the Craft Yarn Council can be found here: http://www.craftyarncouncil.com/chart_knit.html