I worked at Google 2001-2006 and we definitely talked about "database shards", particularly for the AdWords MySQL database. (this architecture has long, long since changed). At least from 2002, and the database was partitioned far before that. I remember at the time thinking the term "shard" was odd but perhaps Ultima Online inspired.

I'm curious now about the history of database partitioning. So much of the early work was about trying to hide the partitions, to pretend it was all one big reliable system. It took awhile for folks to realize that was foolish.