Chain (ch)  -- Yarn over and draw through previous loop.  (To begin a chain, make a slipknot and place on hook.) 

Slip Stitch (sl st) -- Insert hook in stitch, yarn over and draw loop through stitch and loop on hook.

Single Crochet (sc) -- Insert hook in stitch, yarn over and pull up loop (2 loops on hook), yarn over and draw through remaining 2 loops.

Double Crochet (dc) -- Yarn over, insert hook in stitch, yarn over and pull up loop (3 loops on hook), yarn over and draw through 2 loops, yarn over and draw through remaining 2 loops.

Half Double Crochet (hdc) -- Yarn over, insert hook in stitch, yarn over and pull up loop (3 loops on hook), yarn over and draw through remaining 3 loops.

Triple Crochet (tr) -- Yarn over twice, insert hook in stitch, yarn over and pull up loop (4 loops on hook), yarn over and draw through 2 loops, yarn over and draw through 2 loops, yarn over and draw through remaining 2 loops.

Yarn over (yo) -- wrap the yarn from back to front around the hook.

Slipknot -- The initial loop to begin a crocheted item. Make a small loop about 4" from end of yarn, pass the end behind the loop (looks like a circle with slash through it), insert the hook to pick up the  "slash" and tighten both ends of yarn around the hook.