Onomatopœia

Onomatopœia, formations of words resembling in sound that of the things denoted by them.

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

Onega, Lake * Ontario
Oman
Omar
Omar Khayyám
Omar Pasha
O'Meara, Barry Edward
Ommiades
Omnipresence
Omphalë
Omsk
Onega, Lake
Onomatopœia
Ontario
Ontario, Lake
Ontology
Onyx
Oosterzee, Jan Jakob van
Opal
Open Secret, The
Open, Sesamë
Opera
Opera Bouffe