Each has a horizontal line at the top and short diagonal lines through them. The symbol resembles a shell with five straight lines, two angled outward on the left and two angled outward on the right with a straight vertical line in the middle. The 5-dc shell is for a 5 double crochet shell stitch.There is a short diagonal line through each of the five lines. There is also a straight line in the middle and a horizontal upward curved line at the top where the five meet. 5-dc popcorn is the 5 double crochet popcorn stitch. The symbol for this shows two lines curving inward on the left and the opposite on the right.The symbol for this is the same as the 3-dc cluster above but without the short diagonal lines. 3-hdc cluster/puff st/bobble is a 3 half double crochet cluster, puff, or bobble stitch (your pattern should clarify which).There is a short diagonal line through each of the three lines.
There is also a straight line in the middle and a horizontal line at the top where the three meet. The symbol for this is a line curving inward on the left and the opposite on the right.
3-dc cluster is a 3 double crochet cluster stitch.There is a short diagonal line going through each of the three sides and a horizontal line across the top where the three points meet. The symbol for this looks like a taller isosceles triangle without the bottom but with a straight line in the middle. Dc3tog means to double crochet 3 stitches together.Starting at the top of the right column and going down: There is a short diagonal line going through each of the two sides and a horizontal line across the top where the two points meet. The symbol for this looks like a taller isosceles triangle without the bottom. Dc2tog means to double crochet 2 stitches together.There is a short diagonal line going through each of the three sides. The symbol for this also looks like an isosceles triangle without the bottom but with a straight line in the middle. Sc3tog means to single crochet 3 stitches together.There is a short diagonal line going through each of the two sides. The symbol for this looks like an isosceles triangle without the bottom. Sc2tog means to single crochet 2 stitches together.The double treble/triple crochet (dtr) is a stitch that is shown as a T shape with three short diagonal lines through the vertical part of the symbol.The treble/triple crochet (tr) is another basic stitch and is shown as a T shape with two short diagonal lines through the vertical part of the symbol.The double crochet (dc) is another basic stitch and is shown as a T shape with one short diagonal line through the vertical part of the symbol.The half double crochet (hdc) is another basic stitch and is shown as a T shape.Single crochet (sc) is a basic crochet stitch that is shown as a cross or X on a crochet diagram.A slip stitch (sl st) is used to connect stitches and is usually shown as a back/colored dot, filled-in oval, or a dash.This is the base set of stitches for most patterns. The chain stitch (CH) is usually shown as a horizontal oval shape.
Starting at the top of the left column and going down:
Not that a diagram may have slightly different versions of what you see in the chart above but most are very close to what's shown. For further explanation, we'll quickly go over these common symbols and what they mean.