Symbol

ok guys, this have been torturing me since years, I have a necklace ( not the one in the picture) with that symbol, i liked that symbol too much, that I Included it on Drake's shirt, but there's a problem, I don't know what does that symbol means, if somebody know the meaning of that symbol or can find info about it, please tell me, I'll be very thankful, the only clue that i have, is that is a celtic symbol