D defs.my
Entry 2 senses Webster, 1913

Whereon

· Where·on · IPA
01 adv. On which; -- used relatively; as, the earth whereon we live.
  1. 1.
    On which; -- used relatively; as, the earth whereon we live.
    “O fair foundation laid whereon to build.” Milton.
  2. 2.
    On what; -- used interrogatively; as, whereon do we stand?