Luckily means fortunately, as things turned out. Luckily nobody was hurt, luckily for us, luckily it stopped.
It comments on the whole sentence rather than the verb, which is why it sits at the front. It marks a good outcome nobody arranged, which is the difference from thankfully.
1adverbluckilyFortunately, as things turned out.
“I missed the bus, but luckily my neighbour gave me a lift.”
luckily is a manner.
Middle English
lukky
English
lucky
English, today
luckily
From lucky + -ly. lucky comes from Middle English lukky, equivalent to luck + -y. Cognate with Scots lucky (“lucky”), West Frisian lokkich (“lucky, fortunate”), Dutch gelukkig (“lucky, fortunate, happy”). Compare also Danish lykkelig (“happy”), Swedish lycklig (“happy, lucky”), German glücklich (“happy”), stq glukkelk (“happy”).
Etymology from Wiktionary, CC BY-SA