O - Encyclopaedia

Click a letter for the index

Or search the encyclopaedia:

 

 

Go

 

O
O grade
O Henry
O'Casey, Seán
O'Connell, Daniel
O'Connor, (Mary) Flannery
O'Connor, Frank
O'Flaherty, Liam
O'Higgins, Bernardo
O'Keeffe, Georgia
O'Neal, Shaquille Rashaun
O'Neill, Eugene Gladstone
O'Reilly, Tony (Anthony Joseph Francis)
O'Toole, Peter (Seamus)
O-Bon
oak
Oakland
oarfish
OAS
oasis
Oasis
oat
Oates, Laurence Edward Grace
Oates, Titus
oath
OAU
Oaxaca (city)
Ob
OBE
obelisk
Oberammergau
Oberon
obesity
obi
obituary
object (computing)
object (grammar)
object-oriented programming
oblique projection
oboe
Obote, (Apollo) Milton
obscenity law
observatory
obsession
obsessive-compulsive disorder
obsidian
obstetrics
Occam, William of
occult
occupation
ocean
ocean current
Ocean Drilling Program
ocean trench
Oceania
Oceanic art
oceanography
ocelot
Ockham, William
octagon
octane rating
octave
Octavian
octet rule
October Revolution
Octobrists
octopus
ode
Oder
Odessa (Ukraine)
Odin
Odra
Odysseus
OE
OECD
oedema
Oedipus
Oedipus complex
oesophagus
oestrogen
oestrus
Offa
Offa's Dyke
Offaly
Offenbach, Jacques
office suite
Official Secrets Act
offline browsing
offline editing
offset printing
Oflot
Ogaden
Ogasawara-shoto
Ogoni
Ogun
Ohio (river)
Ohio (state)
ohm
Ohm's law
OHMS
oil
oil crop
oil paint
oil palm
oil refinery
oil spill
oil, cooking
Oise (river)
okapi
Okavango Delta
Okhotsk, Sea of
Okinawa
Oklahoma
Oklahoma City
Oklahoma Land Run
okra
Okri, Ben
Olaf (I) Tryggvesson
Olaf (II) Haraldsson
Olaf V
Old Catholic
Old English
Old English literature
Old Pretender
Old Testament
Old World
old-age pension
Oldenburg, Claes Thure
Olduvai Gorge
oleander
olefin
oligarchy
Oligocene epoch
oligopoly
oligosaccharide
olive
olive branch
olivenite
Olives, Mount of
Olivier, Laurence (Kerr)
olivine
olm
Olmec
Olmert, Ehud
Olympia (Greece)
Olympic Games
Olympus
Om
Oman
Omar
Omar Khayyám
Omayyad dynasty
ombudsman
Omdurman
Omdurman, Battle of
omnivore
Omsk (city)
onager
Onassis, Aristotle Socrates
onchocerciasis
onco-mouse
oncogene
oncology
one-party state
Onega, Lake
Onezhskoye Ozero
onion
online system
onomatopoeia
onset
Ontario
Ontario, Lake
ontogeny
onyx
oolite
Oort cloud
Oort, Jan Hendrik
oosphere
Oostende
ooze
op art
op. cit.
opal
opaque
OPEC
Open College
open punctuation
open shop
open source
Open University
open-hearth furnace
opencast mining
opera
operating system
operational amplifier
operetta
operon
Ophüls, Max
Ophiuchus
ophthalmia neonatorum
ophthalmology
opiate, endogenous
opinion poll
opium
Opium Wars
opossum
Oppenheimer, J(ulius) Robert
opposition
Opposition, Leader of His/Her Majesty's
optic nerve
optical character recognition
optical disk
optical fibre
optical illusion
optical mark recognition
optics
optimum population
opting out
option
optoelectronics
opuntia
Opus
oracle
Oracle
oral literature
Oran
orang-utan
orange
Orange (river)
Orange Order
Orange, House of
Orangeman
Oratorian
oratorio
orbit (astronomy)
orbital, atomic
orchestra
orchestration
orchid
ordeal, trial by
order (architecture)
order (biology)
order in council
ordinal number
ordinate
ordination
Ordnance Survey
Ordovician period
ore
oregano
Oregon
Orenburg (city)
Orestes
orfe
Orff, Carl
Orford, 1st Earl of
organ (anatomy)
organ (music)
organelle
organic chemistry
organic farming
Organization for Economic Cooperation and Development
Organization for Security and Cooperation in Europe
Organization of American States
Organization of Arab Petroleum Exporting Countries
Organization of Petroleum-Exporting Countries
Organization of the Islamic Conference
organizer
orienteering
original sin
Orinoco
oriole
Orion (astronomy)
Orion nebula
Orissa
Orkney Islands
Orléans
Orlando
Orly
Ormuzd
ornamentation
ornithology
ornithophily
orogenesis
Orpheus
Orphism (art)
orrery
orris root
Ortega Saavedra, Daniel
orthochromatic
orthodontics
Orthodox Church
Orthodox Judaism
orthographic projection
orthopaedics
Orton, Joe (John Kingsley)
Orvieto
Orwell, George
oryx
Osaka
Osborne, John James
Oscar II
oscillating universe
oscillation
oscillator (physics)
oscillograph
oscilloscope
osier
Osiris
Oslo
Osman I
osmium
osmoregulation
osmosis
osprey
Ossa, Mount
Ossetia
Ossian
ossification
Ostend
osteomyelitis
osteopathy
osteoporosis
Ostia
ostinato
ostrich
Ostrogoth
Oswald, St
Othman
Othman I
Otho I
Otis, Elisha Graves
otitis
otosclerosis
Ottawa
otter
Otto cycle
Otto I
Otto IV
Ottoman Empire
OU
Ouagadougou
Oudh
Oughtred, William
ounce (animal)
ounce (mass)
Ouse, Great
out-of-town shopping
outback
Outer Hebrides
outlawry
Outlook Express
output device
outsider art
ouzel
ovary
overdraft
overfishing
Overijssel
overlander
overpopulation
overtone
overture
Ovett, Steve(n) Michael James
Ovid
oviparous
ovoviviparous
ovulation
ovule
ovum
Owen, Michael James
Owen, Robert
Owen, Wilfred Edward Salter
Owens, Jesse
owl
ox
oxalic acid
oxbow lake
Oxfam
Oxford
Oxford and Asquith, Earl of
Oxford Movement
Oxfordshire
oxidation (chemistry)
oxide
oxlip
Oxon.
oxpecker
oxyacetylene torch
oxygen
oxygen debt
oxymoron
oyster
oyster catcher
oz
Ozalid process
Ozark Plateau
Ozero Balkhash
Ozero Baykal
ozone
ozone depleter
ozone layer
Ozu, Yasujiro

Yellow symbolizes the golden land of South America. Red stands for courage and the blood of the freedom fighters. Blue represents the ocean separating South America from Spain. Effective date: 17 February 1954. >>