Where does “rhegennod” come from?

rhegennod (Welsh) comes from Welsh od, from Middle English odde, from Old Norse oddi, from Old Norse -i, from Latin -ē, from Latin dis-, from Latin calceus, from Latin calx — small stone, pebble; gravel, rubble.

Ancestry of “rhegennod”, step by step

rhegennod traces back through two separate lines of ancestry.

via Welsh od

Step	Language	Word	Meaning
1	Welsh	od	odd, strange; odd
2	Middle English	odde	inflection of od: ## weak singular ## strong/weak...
3	Old Norse	oddi	odd, third or additional number; triangle
4	Old Norse	-i	th
5	Latin	-ē	ly; used to form adverbs from adjectives
6	Latin	dis-	asunder, apart, in two; reversal, removal;...
7	Latin	calceus	shoe
8	Latin	calx	limestone; chalk; the finish line
9	Ancient Greek	χάλιξ	small stone, pebble; gravel, rubble

via Welsh rhegen

Step	Language	Word	Meaning
1	Welsh	rhegen	rail bird, crake (Rallidae)

Every word from Ancient Greek χάλιξ →Every word from Latin dis- →Every word from Latin -ē →