attested

1. participlepastsimple past and past participle of attest

comparative more attested · superlative most attested

1. Proven; shown to be true with evidence.
2. Supported with testimony.
3. Certified as good, correct, or pure.

   A Contract of eternall bond of loue, Confirm'd by mutuall ioynder of your hands, Atteſted by the holy cloſe of lippes,

   c. 1601–1602 (date written), William Shakespeare, “Twelfe Night, or What You Will”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene i]

4. human sciencesOf words or languages, proven to have existed by records.

   The word "slæpwerig" (sleep-weary) is attested in the Exeter Book in the form "slæpwerigne".

   1 more example

   A term should be included if it's likely that someone would run across it and want to know what it means. This in turn leads to the somewhat more formal guideline of including a term if it is attested and idiomatic.

   2010, Alexander Humez, Nicholas Humez, Rob Flynn, Short Cuts: A Guide to Oaths, Ring Tones, Ransom Notes, Famous Last Words, and Other Forms of Minimalist Communication, Oxford University Press US, →ISBN, page 33