I've seen "indicia" in legal documents--most recently in the Ukraine scandal whistleblower report ("preliminary review identified some indicia of an arguable political bias"). Is it just a more formal legalistic synonym for "indications" or is there a subtle distinction?
The OED says that an indicium[paywalled link] is an indication, sign, or token. They also say that this loanword from Latin is chiefly used in its plural form, indicia.
The word has been used in English texts since the 17th century. It’s a reasonably common term (at least in formal text) from the OED's “frequency band four”. Here are two of the 19th-century citations they provide, the first from fiction and the second from nonfiction: [italics in originals]
- 1815 Walter Scott Guy Mannering I. x. 154
The corpse afforded no other indicia respecting the fate of Kennedy.
- 1862 George Cornewall Lewis Survey of the Astronomy of the Ancients iv. 1
We may perhaps rather wonder that Hipparchus should have succeeded in discovering this truth by means of the far and faint indicia which were within his reach.
As shown above, the term has sometimes been set in italic to show that it's an unassimilated foreign term, which isn't altogether surprising what with how it's retained its original -um/-a endings from Latin's second-declension neuters.