Doug's not getting much help here, so as someone who uses said acronyms, here are the ones I use and their meanings:
- PLA means pre-light aroma, aka the sniff test resulting in a whiff of... usually just tobacco, at least in my case. As I've mentioned in various reviews, my sniffer ain't up to much so I rarely detect the aromas others get.
- PLD means pre-light draw, or how tight or open the draw is. I think some use it to also mean the flavors they detect from sucking on an unlit cigar. I don't use it that way as I rarely get any flavors that way.
- I think I've seen PLT used, which I believe is intended to mean pre-light taste. See PLD above...