a.

1. 可作為手段的；有幫助的[F][（+in/to）]
   Her help was instrumental in tracking down the criminal.

   她的協助對追捕到罪犯起了相當作用。

2. （使用）器械的；（使用）儀器的
   instrumental navigation

   儀表導航

3. 用樂器演奏的；為器樂譜寫的
   He composed both vocal and instrumental music.

   他既譜寫聲樂曲也譜寫器樂曲。

4. 【哲】工具主義的
5. 【語】工具格的

n.[C]

1. 器樂曲
2. 【語】工具格；工具字（或片語）

adj.

1. serving as a means of pursuing an aim.
2. (of music) performed on instruments, with no vocals.
3. relating to an implement or measuring device.
4. Grammar  denoting or relating to a case of nouns and pronouns indicating a means or instrument.

n.