Thence means from that place or that fact, in old use. Thence to London, and thence it follows, thence onward.
It belongs with hence and whence, and all three are archaic outside legal and formal writing — hence has survived best. The -ce ending marks from: hence is from here, thence from there, whence from where. Note that from thence is redundant and was common anyway.
1adverbthenceFrom that place or that fact.
“We flew to Singapore and thence to Sydney.”
thence is an adverb of place.
Middle English thennes is thenne, from there, plus an adverbial ending. Hence and whence are formed the same way.
Proto-West Germanic
*þananā
Middle English
þennes
English, today
thence
From Middle English þennes, from þenne + -es, the former from þanan, þanona, from Proto-West Germanic þananā. Cognate with Westphalian Low German diëne.
Etymology from Wiktionary, CC BY-SA