Looking at a single academic paper's citation count won't reveal much about a term's historical currency.
For example, there are also papers in Google Scholar (findable via query [database shard], through 1987) mentioning this same SHARD system in 1986 and 1987, with 33 and 97 citations respectively. And further, there's a 1986 MIT technical note that mentions a commercially-in-development version of this SHARD system, but refers back to a 1985 paper, "System architecture for partition-tolerant distributed databases", as an authoritative source about SHARD – though that 1985 paper doesn't declare the name SHARD.
That's suggestive that SHARD was adopted as a catchy name for that particular work around 1985-1986, then becoming more widespread in the 1986-1988 timeframe.
But perhaps more interesting: that original 1985 paper mentions in its acknowledgements Hector Garcia-Molina – a definite 'hub' person in databases/indexing/networked-information for decades, among many other things Google cofounder Sergey Brin's advisor at Stanford from 1993-1997. (See: <https://en.wikipedia.org/wiki/H%C3%A9ctor_Garc%C3%ADa-Molina...)
So it's likely safe to assume that from the late 80s into the 90s, top CS students/researchers around the world discussing partitioned distributed databases would often have this particular sense of SHARD mentioned to them, or appear in their readings.
Notably, that 1985 SHARD involved a system where each replica contained the entire database – so did not capture the modern connotations of 'shard', as horizontal partitions. But that vivid & apropos analogy was "in the air" around partitioned/distributed databases.
Thus I'd strongly suspect uses in the modern, non-overlapping sense in that same era, likely predating Ultima Online's 1996ish use. (I'd especially look around precursor work to the 1997 'Consistent Hashing' paper, & other caching-centric work – because there the idea of partition-by-key was central.)
So UO might have devised, but I'd guess more likely popularized, our modern sense of 'sharding'.
It's interesting to learn more about the history here. When UO came out and used the shards concept I just assumed it was a callback to 1988's Ultima 5 and the shards of Mondain's gem. Linguistic history sure is blurry and organic!
For example, there are also papers in Google Scholar (findable via query [database shard], through 1987) mentioning this same SHARD system in 1986 and 1987, with 33 and 97 citations respectively. And further, there's a 1986 MIT technical note that mentions a commercially-in-development version of this SHARD system, but refers back to a 1985 paper, "System architecture for partition-tolerant distributed databases", as an authoritative source about SHARD – though that 1985 paper doesn't declare the name SHARD.
That's suggestive that SHARD was adopted as a catchy name for that particular work around 1985-1986, then becoming more widespread in the 1986-1988 timeframe.
But perhaps more interesting: that original 1985 paper mentions in its acknowledgements Hector Garcia-Molina – a definite 'hub' person in databases/indexing/networked-information for decades, among many other things Google cofounder Sergey Brin's advisor at Stanford from 1993-1997. (See: <https://en.wikipedia.org/wiki/H%C3%A9ctor_Garc%C3%ADa-Molina...)
So it's likely safe to assume that from the late 80s into the 90s, top CS students/researchers around the world discussing partitioned distributed databases would often have this particular sense of SHARD mentioned to them, or appear in their readings.
Notably, that 1985 SHARD involved a system where each replica contained the entire database – so did not capture the modern connotations of 'shard', as horizontal partitions. But that vivid & apropos analogy was "in the air" around partitioned/distributed databases.
Thus I'd strongly suspect uses in the modern, non-overlapping sense in that same era, likely predating Ultima Online's 1996ish use. (I'd especially look around precursor work to the 1997 'Consistent Hashing' paper, & other caching-centric work – because there the idea of partition-by-key was central.)
So UO might have devised, but I'd guess more likely popularized, our modern sense of 'sharding'.