E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Onion Pennies.
Roman coins dug up at Silchester; so called from one Onion, a giant, who, the country people say, inhabited the buried city. Silchester used to be called by the British
Ard-Oneoni.e. Ardal Onion (the region of Einion or Onion).