• (adv.) On which; -- used relatively; as, the earth whereon we live. • (adv.) On what; -- used interrogatively; as, whereon do we stand? Found on http://thinkexist.com/dictionary/meaning/whereon/
Where·on' adverb 1. On which; -- used relatively; as, the earth whereon we live. « O fair foundation laid whereon to build.» Milton. 2. On what; -- used interrogatively; as, whereon do we stand? Found on http://www.encyclo.co.uk/webster/W/29