also: ローソクのしん
noun
candle wick
Refers specifically to the wick of a candle, the string that burns.
蝋燭の芯が短くなったので、火が消えそうだ。
The candle wick has become short, so the flame is about to go out.
新しい蝋燭の芯を買ってきてください。
Please buy a new candle wick.
Compound of 蝋燭 (candle) + の (possessive particle) + 芯 (wick). The kanji 芯 originally refers to the pith or core of a plant, extended to mean wick.