One of the mysteries of the English language finally explained.
Definition of adiaphoron in English:
adiaphoron
noun
Usually in plural An issue or practice not considered to be central to a religion, especially Christianity; a religious matter that allows latitude; a non-essential element of a faith. Also: something of a morally neutral nature; a thing which is neither inherently good nor bad.
adjective
In predicative use. Of the nature of an adiaphoron or adiaphora.
Origin
Mid 16th century; earliest use found in Richard Taverner (?1505–1575), translator and evangelical reformer. From post-classical Latin adiaphoron (usually in plural, adiaphora) from ancient Greek ἀδιάϕορον (usually in plural, ἀδιάϕορα), something neither good nor bad, use as noun of neuter of ἀδιάϕορος indifferent.