Attested

Words such as "aselway," "aselkim," "tayri," "adabu," and "amulli" are all derived from various Berber lexical roots that have never been attested in the now impoverished Kabyle dialect.

It's absolutely useless to deny the existence of the Berber language. In fact, words such as "aselway," "aselkim," "tayri," "adabu," and "amulli" are all derived from various Berber lexical roots that have never been attested in the now impoverished Kabyle dialect.

The fact that Shah Jahan built the structure is attested to by the official Persian-language chronicles and other accounts of the period, as well as by the historical accounts and travelogues written by some 17th-century European travelers, said the professor of medieval history.

Jesus is typically referred to in Hebrew as Yeshu, a shortening of Yeshua (itself a shortening of Yehoshua) that is attested as having been in use during his time.

The ancient kingdom of Israel was located in present-day Samaria, and is attested early in inscriptions from the region.

The Philistines were one of the Sea Peoples attested by Ancient Egypt, and came to settle on the western coast of what would eventually become known as Palestine.

Is it attested?

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

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

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.