Twisted single crochet stitch is a one of the basic crochet stitches.
At all crochet schemes twisted single crochet stitch symbol would appear as:
At the scheme below you can see a stitches of twisted single crochet stitch.
Twisted single crochet stitch instructions
Insert your hook in the last stitch of the previous row under top two Pull the yarn back through the loop. Rotate the hook anticlockwise 360 degrees.
Catch the yarn and pull it back through the two loops.
Repeat the preceding steps in each stitch across the row.
The final row crocheted with twisted single crochet stitches looks decorative and voluminous.
Save this step by step tutorial as a reminder