That's the SRT (used to be R/TOriginally Posted by ct9a gsr
)label now. Based on what I've read, Mopar sort of began as performance thing but is now a generic label given to Dodge/Chrysler/Plymoth/Jeep vehicles.
Here are two explanations I found on various MOPAR sites:
"That one is easy...The word Mopar originated many years ago as an acronym for Motor Parts, the parts producing arm of the Chrysler Corporation. People who raced Chrysler products of any make came to call their racers Mopar products rather than by their individual names."
"In the early times of tinkering at the track it was covert operations of the research branch at chrysler when they were building there first factory drag car. Management Of Power And Research."