spark plug

spark-plug的词性：
n.（名词）

1. A device inserted in the head of an internal-combustion engine cylinder that ignites the fuel mixture by means of an electric spark.
火花塞：塞在内燃机汽缸口的设施，通过电火花点燃汽油混合物

2. Informal One who gives life or energy to an endeavor.
【非正式用语】 （事业的）带头人：将生命或能量奉献给某一努力的人