キー

noun

key (for a lock)

Physical key for a lock, door, or ignition.

• 家いえのキーを忘わすれてしまった。

  I forgot my house key.

noun

key (of a piano, keyboard, etc.)

A single key on a musical instrument or computer keyboard.

• ピアノのキーを一ひとつずつ押おしてみた。

  I pressed each piano key one by one.

noun

key (music)

Musical key; the tonal center of a piece. Often used with 調.

See also: 調

• この曲きょくはハ長ちょう調ちょうのキーで書かかれている。

  This piece is written in the key of C major.

noun

key (to solving something); clue

Figurative key or crucial piece of information for solving a problem or mystery.

• 事じ件けん解かい決けつのキーは彼かれの証しょう言げんだった。

  The key to solving the case was his testimony.

noun-modifying (irregular)

key (person, point, etc.); most important

Prenominal use meaning crucial or most important; often in compounds like キーパーソン or キーポイント.

• 彼かれはこのプロジェクトのキーパーソンだ。

  He is the key person for this project.