Candles on a birthday cake
A birthday candle was a small type of candle used to decorate birthday cakes. The birthday person was supposed to blow them out and make a wish. (ENT: "Cold Station 12",TNG: "Future Imperfect", "Parallels", DS9: "The Assignment", VOY: "Twisted", "Before and After", "Latent Image", "Tinker Tenor Doctor Spy")
In 2376, Tuvok claimed to have blown out his birthday candle because it was a fire hazard. (VOY: "Fury")
In 2380, the birthday cake for a Prime daughter who was turning 100 featured candles in the shape of the number 100. (LD: "Veritas")