[Fifth Business]

Pray tell, good man, how therefore should it be defined?

hence=from this place
thence=from that place
whence=from what place

and just for good measure--

whither=to what place
thither=to that place
hither=to this place

They're hard to keep track of without some mnemonic device. Any takers?

[TaxRelief]

thence=from that time

[SFConservative]

How about:

flatulence=from some place