orange filefish
A filefish of species Aluterus schoepfii, typically found along the Central American coast.

orange pipefish
Maroubra yasudai, a species of pipefish.

orange roughy
An edible deep-sea fish (Hoplostethus atlanticus), of the slimehead family (Trachichthyidae).

orange-throated whiptail
Aspidoscelis hyperythrus, a species of teiid whiptail.

orangies
plural of orangie

oras
plural of ora

orbicula
A dorsal sclerite over a hymenopteran arolium; a hard exoskeletal feature with species-specific shape that overhangs and protects the adhesive tip of such an insect's leg and around which the claw(s) curl. Abbreviation "or" or "rb".
A discina (brachiopod).

orbiculae
plural of orbicula

orbicularian
Any spider of the clade Orbiculariae.

orbicularians
plural of orbicularian

orbiculas
plural of orbicula

orbweb
The web of an orbweaver spider

orbwebs
plural of orbweb

oreasterid
Any starfish in the family Oreasteridae.

oreasterids
plural of oreasterid

orfe
A fish, the ide, Leuciscus idus.

orfes
plural of orfe

orfray
The osprey.
Alternative spelling of orphrey.

orfrays
plural of orfray

organellogenesis
The creation and development of organelles

organodifferentiation
The differentiation of organs in a developing plant or animal

oribatid
Any of a group of mites of the suborder Oribatida

oribatids
plural of oribatid

orignal
A moose.

orignals
plural of orignal

ornate rainbowfish
Rhadinocentrus ornatus, a species of eastern-Australian rainbowfish.

ornis
A bird.
The birds collectively of a region; avifauna.

ornithes
plural of ornis

ornithichnite
A fossilised footprint left by a bird.

ornithichnites
plural of ornithichnite

ornithichnology
The branch of science that deals with ornithichnites (fossilised bird footprints).

ornithocheiromorph
a member of the clade Ornithocheiromorpha.

ornithocheiromorphs
plural of ornithocheiromorph

ornithodiran
Any birdlike reptile of the clade Ornithodira.

ornithodirans
plural of ornithodiran

ornitholestid
Any member of the family †Ornitholestidae, now superseded by family †Compsognathidae.

ornitholestids
plural of ornitholestid

ornithomorph
A figure in ancient art resembling a bird.

ornithomorphs
plural of ornithomorph

ornithonym
The common name of a (species of) bird.

ornithonyms
plural of ornithonym

ornithonymy
The naming of birds; the creation of common names for birds; the use of bird names.

ornithoses
plural of ornithosis

ornithosis
A zoonotic infectious disease (of birds) caused by a bacterium called Chlamydia psittaci, it can be transmitted to humans and other animals. When carried by any species of bird belonging to the Psittacidae family (parrots), it is called psittacosis or parrot fever.

oromerycid
Any member of the family †Oromerycidae, extinct relatives of camels.

oromerycids
plural of oromerycid

orphanarium
An orphanage.

orphanariums
plural of orphanarium

orthobothriotaxy
The evolution of the form of bothria in animals

orthodrome
A great circle, or part of one.

orthodromes
plural of orthodrome

orthogastropod
Any snail of the subclass Orthogastropoda.

orthogenomics
The application of genomics to orthopedics

orthogonium
right-angled triangle

orthorrhaphan
Any fly of the infraorder Orthorrhapha

orthorrhaphans
plural of orthorrhaphan

orthotriaene
a sponge spicule that has three short rays projecting at right angles from a longer one

orthotriaenes
plural of orthotriaene

orthotropia
The normal absence of heterotropia.

orycteropodid
Any member of the Orycteropodidae, the aardvark and its extinct relatives.

orycteropodids
plural of orycteropodid

oryzomyine
Any member of the rodent tribe Oryzomyini, including the rice rats.

oryzomyines
plural of oryzomyine

oscar
A cichlid fish of species Astronotus ocellatus, native to South America, sometimes kept in aquariums.

oscarellid
Any of the family Oscarellidae of marine sponges.

oscarellids
plural of oscarellid

oscars
plural of oscar

oscillogenesis
The generation of physiological oscillations

osetrs
plural of osetr

osmoconformer
Any marine invertebrate that maintains its internal salinity such that it is always equal to the surrounding seawater

osmoconformers
plural of osmoconformer

osmoconformist
Synonym of osmoconformer.

osmoconformists
plural of osmoconformist

osmoprotectant
Any osmolyte that helps an organism to survive osmotic stress.

osmoprotectants
plural of osmoprotectant

osmosensitivities
plural of osmosensitivity

osmosensitivity
An organism's degree of sensitivity to osmotic gradients

osmotaxis
movement of an organism in an osmotic pressure gradient

osmotroph
Any osmotrophic organism

osmotrophs
plural of osmotroph

ossaria
plural of ossarium

ossarium
An ossuary.

ossicusp
The bony horn of an okapi or a giraffe.

ossicusps
plural of ossicusp

ossuarium
A charnel house; an ossuary.

ossuariums
plural of ossuarium

ostarioclupeomorph
Any teleost of the cohort Ostarioclupeomorpha

ostarioclupeomorphs
plural of ostarioclupeomorph

ostariophysan
Alternative form of ostariophysian.

ostariophysans
plural of ostariophysan

ostariophysian
A member of the fish superorder Ostariophysi.

ostariophysians
plural of ostariophysian

osteolaemine
A crocodile of the subfamily Osteolaeminae.

osteolaemines
plural of osteolaemine

osteometry
The measurement of the bones of the skeleton (both human and animal)

ostiarii
plural of ostiarius

ostiarius
An ostiary; a doorman; a porter.
A student office held by a prefect with the duties of keeping order, collecting the vulguses, and ensuring the other students attend class.

ostomies
plural of ostomy

ostomy
A surgical procedure to provide an exit point for the waste of an organism.
An exit point created by such surgical procedure.

ostracoderm
Any of the armored jawless fishes of the Paleozoic.

ostracoderms
plural of ostracoderm

ostracodes
plural of ostracode

ostreacean
Any bivalve mollusc of the Ostreacea

ostreaceans
plural of ostreacean

ostreaculture
Archaic spelling of ostreiculture (“oyster farming”).

ostreiculture
oyster farming

ostreid
Any member of the family Ostreidae, the oysters.

ostreids
plural of ostreid

ostreolith
A fossil consisting of accumulated oyster shells.

ostreoliths
plural of ostreolith

otarid
Alternative form of otariid.

otarids
plural of otarid

otariid
Any member of the Otariidae: Synonym of eared seal.

otariids
plural of otariid

otitid
Any species of the family Otitidae (now Ulidiidae) of picture-winged flies.

otitids
plural of otitid

otoceratid
Any ammonite in the family Otoceratidae.

otoceratids
plural of otoceratid

otocinclus
Any of the species of small South American freshwater fish of the genus Otocinclus, popular in home aquariums.

otocincluses
plural of otocinclus

otodontid
Any in the family Otodontidae of extinct sharks.

otodontids
plural of otodontid

otoitid
Any ammonite in the family Otoitidae.

otoitids
plural of otoitid

otophysan
Any of the fish of the Otophysi series within the Ostariophysi superorder, also known as the Otophysa in some classifications.

otophysans
plural of otophysan

otophysian
Alternative form of otophysan.

otophysians
plural of otophysian

otterhound
Alternative form of Otterhound.

otterhounds
plural of otterhound

otterskin
The pelt of an otter.

otterskins
plural of otterskin

ottersona
A fursona that is an otter.

ottersonas
plural of ottersona

ottertaur
A taur with the lower body of an otter.

ouarine
A howler monkey (Alouatta spp.).

ouarines
plural of ouarine

ouistiti
Alternative form of wistiti.

ouistitis
plural of ouistiti

oulachan
Alternative form of eulachon.

oulachans
plural of oulachan

oulachon
Alternative form of eulachon.

oulachons
plural of oulachon

oulakan
Alternative form of eulachon.

oulakans
plural of oulakan

ourang
An orangutan.

ourangs
plural of ourang

ousel
Alternative form of ouzel.

ousels
plural of ousel

outard
The Canada goose.

outarde
Alternative form of outard.

outardes
plural of outarde

outards
plural of outard