Glossarist
http://www.glossarist.com/
To search for specialized vocabulary. "A searchable subject index of about 6,000 different glossaries covering dozens of different topics."
Glassarist
: 2003
slang
Dictionary of Slang
http://www.peevish.co.uk/slang/
"Focuses on slang heard in the UK. Browse by letter, or do search. Shows place of origin, usage (such as humorous, vulgar, derogatory, etc.).
Peevish
: 2003
Probert Encyclopedia of Slang
http://www.probertencylopaedia.com/slang.htm
"Browseable by first letter or searchable by keyword. The slang is from all over the world, not just English."
Probert
: 2003