DATUMS
Verb
datums
Third-person singular simple present indicative form of datum
Noun
datums
plural of datum
Usage notes
This plural is permissible only in the sense of "fixed reference points". For all other senses, the plural is data.
Source: Wiktionary
DATUM
Da"tum, n.; pl. Data. Etym: [L. See 2d Date.]
1. Something given or admitted; a fact or principle granted; that
upon which an inference or an argument is based; -- used chiefly in
the plural.
Any writer, therefore, who . . . furnishes us with data sufficient to
determine the time in which he wrote. Priestley.
2. pl. (Math.)
Definition: The quantities or relations which are assumed to be given in
any problem. Datum line (Surv.), the horizontal or base line, from
which the heights of points are reckoned or measured, as in the plan
of a railway, etc.
Source: Webster’s Unabridged Dictionary 1913 Edition