This early surname derives from an Old Welsh personal name Eignion or Enion – from ‘einion’ meaning stability or fortitude. The forename is first recorded in the Pipe Rolls of Shropshire (1159), ‘Ennian filius (son of) Gieruero’ and as Eynon or Eynun (1221).
It is first recorded as a surname in the late 13th Century. Alternate spellings were Heizhnon (1327), Eynon (1327) John Eynon – The Subsidy Rolls of Worcestershire, Onnyon (1568) and Ineon (1593). In the modern idiom the name has twelve spelling variations including Eynon, Inions, Anyan, Onion(s), O’Nions, Hennion etc.. The first recorded spelling of the family name is shown to be that of William Anyun, which was dated 1279, The Hundred Rolls of Buckinghamshire, during the reign of King Edward 1, ‘The Hammer of the Scots’, 1272 – 1307.
Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to “develop” often leading to astonishing variants of the original spelling.
Reference: copyright 1980-2015 name origin research