Amp "timing" ?


I was reading someone raving about the impeccable "timing" of their high-end amp this morning.  I have heard this term tossed around several times recently in my dive back into highish-end audio. 

Can someone please explain what is meant by this term?  Is it snake-oil or confirmation bias?  I just don't understand how a human  can hear  a timing difference of a soundwave unless it's a 2nd+ order reflection.  

Thoughts?
dtximages
Here's what I hear and I don't necessarily attribute it to the amp (though more about that in a minute): when my system sounds 'right' with a good recording, particularly of something like piano music, I hear the attack (with the fundamental) and the harmonics, which decay. There is an aspect of 'timing' to this that gives shape and body to the presentation of the instrument. That is different than what I understand to be "PRAT" and I'm not sure what to attribute it to beyond the recording. I do know that the amps I use on my main system-- the Lamm ML2 SET-- seem to contribute to this because I hear this aspect more through them than some other amps that have been in the system. I'm not staking out any absolute position on this, other than to observe what I hear as an end result. It could also be part of the rest of the chain-- starting with the phono cartridge- where I've heard more emphasis on leading edge with some cartridges (e.g. Lyra) than others ( Airtight). 
I have a Linn now, but my point was that those specific tables had absolutely the same speed, and the music presented was in identical pitch (which I'm extremely sensitive to, as are most people if they know it or not). Maybe the dealer should have been using a crappier table for comparison than an expensive direct drive Denon. I don't think "prat" is a particularly useful term and am glad it's seemingly fallen out of fashion as I rarely see it anymore, even in UK audio mags.
I was doing some tube rolling. I had a bunch in the phono pre and it sounded a little clearer on the night. Few days later, the sound wasn't great. Played an album, "Friends - Manifest!" Not great. Flat, musically all over the place. Put tubes back. Lots better. Everything snapped into focus including timing. 
@tomic601 : " the swing of a sweet light double"

I doubt many people here have any idea what that is referring to.