Where does “dilyw” come from?

dilyw (Welsh) comes from Middle Welsh dilyw, from Proto-Brythonic *dilüw, from Latin dīluvium, from Latin dīluō, from Latin dis-, from Latin calceus, from Latin calx, from Ancient Greek χάλιξ — small stone, pebble; gravel, rubble.

dilyw (Welsh): flood, deluge

Definitions

flood, deluge

Ancestry of “dilyw”, step by step

Step	Language	Word	Meaning
1	Middle Welsh	dilyw	—
2	Proto-Brythonic	*dilüw	—
3	Latin	dīluvium	a flood
4	Latin	dīluō	to wash away
5	Latin	dis-	asunder, apart, in two; reversal, removal;...
6	Latin	calceus	shoe
7	Latin	calx	limestone; chalk; the finish line
8	Ancient Greek	χάλιξ	small stone, pebble; gravel, rubble

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