The Following Are Commonly Used Crochet Abbreviations:

BP back post FPtr front post treble crochet
BPdc back post double crochet grp(s) group(s)
BPsc back post single crochet hdc half double crochet (U.K.: htr-half treble)
BPtr back post treble crochet lp(s) loop(s)
ch chain(s) sc single crochet (U.K.: dc-double crochet)
ch- refers to chain or space previously made
(i.e., ch-1 space)
sc2tog single crochet 2 sts together
ch-sp chain space previously made sk skip(ped)
dc double crochet (U.K.: tr-treble) sl st slip stitch (U.K.: sc-single crochet)
dc2tog double crochet 2 stitches together sp(s) space(s)
dtr double treble (U.K.: trtr-triple treble) t-ch turning chain
FP front post tr treble (U.K.: dtr-double treble
FPdc front post double crochet trtr triple treble (U.K.: qtr-quadruple treble)
FPsc front post single crochet