American To British Conversions
American "single crochet" is British "double crochet", similarly American "double crochet" is British "triple crochet".
Crochet hook size conversion chart from Norns Needlework.
Taken from the Tropical Knitter size conversion guide, reproduced here since that site often seems unreachable from here :(
Your guess is as good as mine. Here's a chart of average gauge for American terminology yarns, which at least puts them in order of weight: fingering, double knitting, sport weight, worsted weight, chunky, bulky.
Yarn comes in fine, medium and heavy. Fine is often referred to as 'fingering' or baby yarn. 'Sport' or 'jumper-weight' yarn is thicker than fingering.
Extra-fine yarns are used in lace-knitting. Some of these are spun as thin as a human hair. A shawl made of this wool might weigh only two ounces but contain 6,000 yards of yarn.
"Worsted" is the term used for what most people think of as sweater yarn but worsted is actually the term for a yarn whose fibers were combed before spinning. This sweater name is more properly called 'double-knitting' in England and 'Germantown' in America.
Heavy yarns are thick ones meant for large needles. Bulky and chunky are synonyms.
[Additional Note on above: To confuse matters more, "Germantown" in the US was a long-standing brand name for a WORSTED weight yarn, knitting at 20 stitches/10cm; NOT at 22 stitches/10cm as one would expect for a DK].
More on US vs. UK yarn weight names, including a rough range of gauges for each designation can be found at:
There are also a few historical British usages for knitting and crochet techniques and stitches included in the International Glossary of Knitting Terms: