E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
One of the four great public ways made in England by the Romans. The other three are Watling Street, Ikenild Street, and the Fosse. Germanicus derives Ermin from Hermës, whence Irminsull (a column of Mercury), because Mercury presided over public roads. This is not correct; Irminsul, or rather Ermensul, is the Scandinavian Odin, not a Column of Mercury at all; and Erming Street really means Odins Street.
Fair weyes many on ther ben in Englond,
But four most of all ben zunderstond
Fram the south into the north takit Erming-strete;
Fram the east into the west goeth Ikeneld-strete;
Fram south-est [east] to North-west (that is sum del grete)
Fram Dorer [Dover] into Chestre goth Watling-strete;
The forth is most of all that tills from Totëneys
Fram the one end of Cornwall anon to Catenays [Caithness]