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
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.
@n80 well with you, there are at least three of us that will get it....

nobody as yet bit on the Dylan, so my expectations are low...
I was reading someone raving about the impeccable "timing"
  Can someone please explain what is meant by this term?
It all starts with the source, if it doesn't have it then it can't be made up down the line properly, a device like the Schiit Loki can lift it artificially, but your not listening to a flat FR then

Cheers George