Thereafter means after that point in time. Shortly thereafter, thereafter annually, and thereafter.
It belongs to formal and legal writing, where it points back to a moment already named: free for the first year and fifty pounds thereafter. Shortly thereafter is the fixed phrase in narrative. Note the family — thereafter, thereby, therein, thereof, thereupon — which survives almost entirely in contracts and statutes, where the precision is worth the stiffness.
1adverbthereafterAfter that point in time.
“She lived in Paris until she was ten and in London thereafter.”
thereafter is a relation in time.
Old English thaeraefter is there plus after. English built a whole set of these there- and here- compounds, and the legal drafting tradition is what kept them alive.
Old English
þǣræfter — after that; thereafter
Middle English
therafter
English, today
thereafter
From Middle English therafter, theraftir, þerefter, þerafter, þeræfter, from Old English þǣræfter (“after that; thereafter”), equivalent to there + after. Cognate with stq deerätter (“thereafter”), West Frisian dêrefter (“behind that; thereafter”), Dutch daarachter (“behind that; thereafter”), German Low German daarachter (“behind that”), Danish derefter (“thereafter”), Swedish därefter (“thereafter”).
Etymology from Wiktionary, CC BY-SA