Wampler,
Cord=128cu ft. stacked pretty tight. if you're buying.
Looser if you're selling or stacking your own.
"Seasoned" is a subjective term, but in general means wood that has dried so that it ignites readily and burns with a minimum of steam.
Some guys get wrapped around moisture content bieng 20% or less.
1yr Min. if you're buying though, cuz ys don't know how it was "Seasoned" if it was at all. If the bark is loose, it's close enough normally.
As for those giant stacks going to rot, it depends on the local climate and air movement, and the species.
Oak will be fine stacked like that for 5 years uncovered around here.
Boxelder would last 2 before it's mulch.
Also don't forget that some folks with the boilers may very well burn through 20 Cord a season, or might be heating a shop, greenhouse, and thier home.
I go through about 10 Cord easy with 2-3 of it bieng lesser BTU content stuff.
Gimme all Locust or Osage/hedge and I could probably get away with 6.
Stick around and get to reading old posts. LOTS of good info here, and a heck of helpfull gang with knowledge and lore worth sharing.
Stay safe!
Dingeryote