what is /usr/share/dict used for Where is this used, I read the README and it didn't say what program it was from, I do not think that it is the stock dictionary app because I tried some very obscure looking words that were in some of the files and they did not come up in the stock dictionary app. 

Any idea where this comes from?
The origins go way back as a place holder for the dictionary words used by the spell utility. spell is not available but the program look will use the words dictionary. You could use one of these alias/function courteous of Wilfredo Sanchez Jr. to do word look ups.

For ksh, zsh, and bash 

word () { grep -F -i "$*" /usr/share/dict/web2 ; }


For tcsh

alias word  'grep \!* /usr/share/dict/web2'