When I first started running in high school my coach referred to a runner's fastest time in an event as a PR (personal record). I adopted this term and still use it today. However, many timing sites use PB (personal best) instead and I've met people who say PB instead of PR.
I guess PB always meant peanut butter in my head and Puerto Rico isn't featured in enough of my thoughts to displace personal record.
What jargon do you use and why?