Crochet chart symbols
The standardised crochet symbols are commonly used in crochet patterns in addition to or in place of written instructions. The symbols are placed in relation to one another to create a visual form of stich patterns on the right side of the work. The diagram of patterns help to make the instruction clearer and easier to read.
Increase (inc) or decrease (dec) stitches
yo yarn over (USA)
yoh yarn over hook (UK)