Organism

Organism, a structure instinct with life, and possessed of organs that discharge functions subordinate and ministrative to the life of the whole.

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

Orfila, M. J. Bonaventure * Organon
[wait for the fun]
Orcus
Ordeal
Ordericus Vitalis
Orders in Council
Oreades
Oregon
Orelli, Conrad von
Orelli, Johann Kaspar von
Orestes
Orfila, M. J. Bonaventure
Organism
Organon
Orgies
Oriflamme
Origen
Original Sin
Orinoco River
Orion
Orissa
Orkney Islands
Orlando