core · wick

1. Origins, structure, and basic meaning

• Structure: 芯 is read しん, has 7 strokes, and relates to the core or wick of an object.
• Basic usage: 芯 is read しん, and 替え芯 is read かえしん.

2. Common pitfalls and similar expressions

• 芯 and 替え芯
  • 芯 means core or wick.
  • 鉛筆の芯が折れたので削り直した。 means “The pencil lead broke, so I sharpened it again.”
  • 替え芯 means refill or replacement lead.
  • ペンのインクがなくなったので替え芯を買った。 means “My pen ran out of ink, so I bought a refill.”