One in Sixty Million or So

The Perseus Collection of Greek and Roman Materials provides a convenient list of Word Counts by Language. As of half an hour ago, the totals were:

English
(42,956,587 words)
French
(2,001 words)
German
(426,929 words)
Greek
(8,263,757 words)
Italian
(178 words)
Latin
(9,244,457 words)
Old English
(1 word)
Other
(3,318 words)

I want to know how a single word of Old English slipped in among the tens of millions in other languages, why it isn’t listed among the ‘Other’ languages, and — most important — what word is it?