芯

1. Origins, structure, and basic meaning

• Structure: 芯 is read as しん and is a noun for a functional central part such as pencil lead or a candle wick.
• Basic usage: Pencil lead breaking appears in 鉛筆の芯が折れる, while lighting a candle wick appears in ろうそくの芯に火をつける.

2. Common pitfalls and similar expressions

• Meaning by object
  • With a pencil it means lead; with a candle it means the wick that is lit.
• Difference from 中心
  • Compared with the broad word for a spatial or organizational center, this term focuses on the functioning core inside an object.