October

October, the tenth month of the year so called (i.e. the eighth) by the Romans, whose year began on March.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

Octavia * Od
Oceania
Oceanides
Oceanus
Ochils
Ochiltree, Edie
Ochino, Bernardino
Ochterlony, Sir David
Ockley, Simon
O'Connell, Daniel
Octavia
October
Od
Oddfellows
Oder
Odessa
Odin
Odo
Odoacer
O'Donnell, Leopold
Odyssey
Œcolampadius, Joannes