Something is making one thing the same as another inside a period of time. You'll see this word on computer-ish things a lot. This is syncing.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
When I was syncing my iPhone, it turned off and I was a little freaked out.
I wonder why Dropbox always freezes while syncing photos.
It will probably show up soon. My Evernote is syncing right now.