past perfect: a perfective tense used to express action completed in the past
perfective: a tense of verbs used in describing action that has been completed (sometimes regarded as perfective aspect)
vapor lock: a stoppage in a pipeline caused by gas bubbles (especially a stoppage that develops in hot weather in an internal-combustion engine when fuel in the gas line boils and forms bubbles that block the flow of gasoline to the carburetor)