The Fennas word for candle is cainnel. Cainnel is a rare last name. Cainnel seems to be a former Irish word for candle or torch.
How did I come up with this word? The Welsh word for candle is cannwyll, and the Irish word for candle is coinneal.
I didn't mention a Breton word for candle, because I'm not exactly sure what the word is. It's more difficult for me to find words in Breton because there are fewer resources, plus having to translate from French to Breton.