noun
candle wick trimmer; snuffer; douter
A tool for trimming candle wicks or extinguishing candles; a somewhat specialized historical or traditional item.
昔の人は芯切りを使ってろうそくの芯を整えた。
People in the past used a wick trimmer to trim candle wicks.
博物館に古い芯切りが展示されている。
An old snuffer is on display at the museum.
A more general term for a candle extinguisher; 芯切り specifically refers to trimming the wick as well as snuffing.
Compound of 芯 (shin, 'wick') and 切り (kiri, 'cutting'). The alternate kanji 心 may be a phonetic or semantic variant.