expense · spend

1. Origins, structure, and basic meaning

• Structure: The on reading is ひ, and the kun readings are ついやす and ついえる. It has 12 strokes and relates to spending time or money and to the resulting expense.
• Basic usage: 費やす is read ついやす, and 費用 is read ひよう.

2. Common pitfalls and similar expressions

• 費やす / 費用
  • 費やす means to spend. It is a transitive verb read ついやす. It means to spend time, money, or effort on a purpose.
  • 模型の完成までに三か月を費やした。 means “It took three months to complete the model.”
  • 費用 means cost or expense. It is a noun read ひよう. It is the cost or expense required for a repair, trip, task, or similar activity.
  • 修理にかかる費用を事前に確認した。 means “I checked the cost of the repair in advance.”