Where does “Deirdre” come from?

Deirdre comes from Old Irish Derdriu, derived from Old Irish derdrethar, which itself derives from Old Irish dord.

Ancestry of “Deirdre”, step by step

Step	Language	Word	Meaning
1	Irish	Deirdre	—
2	Old Irish	Derdriu	—
3	Old Irish	derdrethar	rages, resounds
4	Old Irish	dord	to buzz, drone; buzzing, humming, droning,...

Deirdre — Etymology, Origin & Word History | Etymology Explorer