Please see a handy stitch and abbreviation guide to help you get your head around those crafty Crochet patterns!
All in UK terminology with references to US where different.
blo - Back Loop Only
Working into the back loop only of the stitch in the previous row/round
ch(s) - Chain(s)
With a loop on the hook, yarn over hook, draw yarn through loop on hook (1 loop on hook). Continue as required
ch-sp(s) - Chain Space(s)
The space made when working a chain or chains between stitches
dc - Double Crochet (US - sc Single Crochet)
Hook into stitch, yarn over hook, draw hook back through the stitch (2 loops on hook),yarn over hook, pull yarn through both loops on hook
dc2tog - Double Crochet 2 Together (US - sc2tog Single Crochet 2 Together)
Hook into stitch, yarn over hook, draw hook back through the stitch (2 loops on hook), hook into next stitch, yarn over hook, draw hook back through the stitch (3 loops on hook), yarn over hook, pull yarn through all loops on hook
dc-spike - Spike Stitch using dc
Working the st into rows below the current row being worked (as defined by pattern), hook into stitch, yarn over hook, draw hook back through the stitch (2 loops on hook),yarn over hook, pull yarn through both loops on hook.
dtr - Double Treble Crochet (US - tr Treble Crochet)
Yarn over hook twice, hook into stitch, yarn over hook, draw hook back through the stitch (4 loops on hook), yarn over hook, pull yarn through first 2 loops, yarn over hook, pull yarn through next 2 loops on yarn, yarn over hook, pull yarn through remaining 2 loops on hook.
dtr2tog - Double Treble 2 Together (US - tr2tog Treble 2 Together)
Yarn over hook twice, hook into stitch, yarn over hook, draw hook back through the stitch (4 loops on hook), yarn over hook, pull yarn through first 2 loops, yarn over hook, pull yarn through next 2 loops on yarn, yarn over hook twice, hook into next stitch, yarn over hook, draw hook back through the stitch (5 loops on hook) yarn over hook, pull yarn through first 2 loops on hook, yarn over hook, pull yarn through next 2 loops, yarn over hook and pull through the remaining stitches on hook
flo - Front Loops only
Working into the front loop only of the stitch in the previous row/round
htr - Half Treble Crochet (US - hdc Half Double Crochet)
Yarn over hook, hook into stitch, yarn over hook, draw hook back through the stitch (3 loops on hook), yarn over hook, pull through all 3 loops on hook.
htr2tog - Half Treble 2 Together (US - hdc2tog Half Double 2 Together)
Yarn over hook, hook into stitch, yarn over hook, draw hook back through the stitch (3 loops on hook), yarn over hook, hook into next stitch, yarn over hook, draw hook back through the stitch (5 loops on hook), pull through all loops on hook.
pc - Popcorn Stitch
Work required number (pattern usually specifies) of stitches into stitch below, remove hook and insert into the top of the first stitch of the group, insert hook into top of last stitch of group, yarn over hook, pull yarn through both stitches.
pf - Puff Stitch
Yarn over hook, hook into stitch, yarn over hook, draw hook back through stitch (3 loops on hook), repeat procedure into the same stitch for the required number of times, when complete, yarn over hook and pull through all loops on hook
RS - Right Side
Work with the front side of your project facing you
sl - Slip Stitch
Hook into stitch, yarn over hook, draw hook back through the stitch (2 loops on hook), draw last loop through first loop
sp(s) - Space(s)
The gap between stitches, whether directly between or made up of chains
st(s) - Stitch(es)
All variations of crochet are referred to as stitches
tr - Treble Crochet (US - dc Double Crochet)
Yarn over hook, hook into stitch, yarn over hook, draw hook back through the stitch (3 loops on hook), yarn over hook, pull yarn through first 2 loops, yarn over hook, pull yarn through remaining 2 loops on hook
tr2tog - Treble 2 Together (US - dc2tog Double Crochet 2 Together)
Yarn over hook, hook into stitch, yarn over hook, draw hook back through the stitch (3 loops on hook), yarn over hook, pull yarn through first 2 loops, yarn over hook, hook into next stitch, yarn over hook, draw hook back through the stitch (4 loops on hook), pull yarn through first 2 loops, yarn over hook and pull yarn through remaining loops on hook
trtr - Triple Treble Crochet
Yarn over hook three times, hook into stitch, yarn over hook, draw hook back through the stitch (5 loops on hook), yarn over hook, pull yarn through first 2 loops, yarn over hook, pull yarn through next 2 loops on yarn, yarn over hook, pull yarn through next 2 loops on hook, yarn over hook, pull yarn through remaining loops on hook
WS - Wrong Side
Work with the back side of your project facing you