Its meaning soon broadened, however, to mean “range of vision” or “sight” on land or sea. A male given name, form of kendall or kenneth See examples of ken used in a sentence.
ken eurich - i clearly missed something because who’s her new bf? : NYCinfluencersnark
In this context, the phrase is infelicitous
' beyond one's ken ', in its ordinary usage, means beyond one's powers of comprehension.
An idea beyond one's ken Range of sight or vision. Ken in american english (ken) noun a male given name, form of kendall or kenneth In common usage a fossil word, found only in phrases such as beyond one’s ken and swim into one’s ken.
There are six meanings listed in oed's entry for the noun ken, two of which are labelled obsolete See ‘meaning & use’ for definitions, usage, and quotation evidence.
