Aulasyawi-uh-see

n. The sadness that there's no way to convey a powerful memory to people who weren't there at the time--driving past your childhood home to show it to a friend, or pointing at a picture of a loved one you lost, only to realize that to them it's just another house, just another face. A contraction of auld lang syne, which is Scots for "times long past"--fragments of which are still present in aulasy, but the meaning has been lost.