WHEN adv.
what time; at, during, or after the time that; at or just after, the moment that; -- used relatively. Kings may Take their advantage when and how they list. Daniel. Book lore ne'er served, when trial came, Nor gifts, when faith was dead. J. H. Newman.
WHENCE adv.
which place, source, material, cause, etc.; the place, source, etc., from which; -- used relatively. Grateful to acknowledge whence his good Descends. Milton.
WHEREOF adv.
Of which; of whom; formerly, also, with which; -- used relatively. I do not find the certain numbers whereof their armies did consist. Sir J. Davies. Let it work like Borgias' wine, Whereof his sire, the pope, was poisoned. Marlowe. Edward's seven sons, whereof thyself art one. Shak.