ophiochitonid
Any brittle star of the genus Ophiochiton

ophiochitonids
plural of ophiochitonid

ophiocomid
Any brittle star in the family Ophiocomidae.

ophiocomids
plural of ophiocomid

ophiodermatid
Any brittle star in the family Ophiodermatidae.

ophiodermatids
plural of ophiodermatid

ophiohelid
Any brittle star of the family Ophiohelidae

ophiohelids
plural of ophiohelid

ophiolepidid
Any brittle star of the family Ophiolepididae.

ophiolepidids
plural of ophiolepidid

ophioleucinid
Any brittle star of the family Ophioleucidae

ophioleucinids
plural of ophioleucinid

ophionereidid
Any brittle star of the family Ophionereididae

ophionereidids
plural of ophionereidid

ophiothamnid
Any brittle star of the family Ophiothamnidae

ophiothamnids
plural of ophiothamnid

ophiothricid
Any in the family Ophiotrichidae of brittle stars.

ophiothricids
plural of ophiothricid

ophiotrichid
Any brittle star in the family Ophiotrichidae.

ophiotrichids
plural of ophiotrichid

opihi
A limpet of genus Cellana.

opisthognathid
Any in the family Opistognathidae of jawfishes.

opisthognathids
plural of opisthognathid

opisthorchid
Any fluke of the family Opisthorchiidae.

opisthorchids
plural of opisthorchid

opistognathid
Alternative spelling of opisthognathid.

opistognathids
plural of opistognathid

opportunitroph
An opportunistic feeder

opportunitrophs
plural of opportunitroph

opsonoid
A supposed substance formed when opsonin combines with bacteria and undergoes heating, preventing further opsonization.

orbitoid
Any foraminifer of the family Orbitoididae.

orbitoids
plural of orbitoid

orbitolinid
Any foraminifer in the family Orbitolinidae.

orbitolinids
plural of orbitolinid

orchal
Obsolete form of orchil.

orchals
plural of orchal

orchel
Alternative spelling of orchil.

orchil
Any of several lichens, especially those of the genera Roccella and Lecanora.
The purple dye, orcein, extracted from them (especially Lecanora tartarea) and often used as substitute for Tyrian purple.

orchils
plural of orchil

oreodontid
Any in the family Oreodontidae (syn. of Merycoidodontidae) of extinct mammals.

oreodontids
plural of oreodontid

organista
Any of several South American wrens of the order Troglodytidae, noted for the sweetness of their song.

organistas
plural of organista

ornithophage
Any organism that eats birds.

ornithophages
plural of ornithophage

ornithosuchid
Any pseudosuchian in the family Ornithosuchidae.

ornithosuchids
plural of ornithosuchid

ornithothoracine
Any avialan of the clade Ornithothoraces

ornithothoracines
plural of ornithothoracine

orthoavulavirus
Any avulavirus of the genus Orthoavulavirus

orthoavulaviruses
plural of orthoavulavirus

orthobunyavirus
Any of the genus Orthobunyavirus of bunyaviruses

orthobunyaviruses
plural of orthobunyavirus

orthoceratid
Any in the family Orthoceratidae of extinct cephalopods.

orthoceratids
plural of orthoceratid

orthograptid
Any graptolite of the genus Orthograptus.

orthogroup
The group of genes descended from a single gene in the last common ancestor of a clade of species.

orthogroups
plural of orthogroup

ortholog
Any of two or more homologous gene sequences found in different species related by linear descent.

orthologs
plural of ortholog

orthologue
One of two or more homologous gene sequences found in different species.

orthologues
plural of orthologue

orthonychid
Any logrunner in the family Orthonychidae.

orthonychids
plural of orthonychid

orthophlebiid
Any scorpionfly of the family Orthophlebiidae

orthophlebiids
plural of orthophlebiid

orthopoxvirus
Any of the genus Orthopoxvirus of poxviruses, including smallpox and many species isolated from mammals.

orthopoxviruses
plural of orthopoxvirus

orthothecid
Any hyolith of the order †Orthothecida

orthothecids
plural of orthothecid

orval
A sage, of species Salvia viridis.

oscillatorian
Any filamentous cyanobacterium of the genus Oscillatoria.

oscillatorians
plural of oscillatorian

osmoregulant
Synonym of osmoregulator.

osmoregulants
plural of osmoregulant

osmoregulator
Any organism that practices osmoregulation

osmoregulators
plural of osmoregulator

osmylid
Any lacewing in the family Osmylidae.

osmylids
plural of osmylid

osphronemid
Any gourami in the family Osphronemidae.

osphronemids
plural of osphronemid

ossicone
Either of the horn-like protuberances on the heads of giraffes and male okapi. Some extinct species in the family bore antler-like ossicones.

ossicones
plural of ossicone

ostiariates
plural of ostiariate

ostodolepid
Any of the extinct family †Ostodolepidae of tuditanomorph microsaurs.

ostodolepids
plural of ostodolepid

otidid
Any species of the bustard family Otididae.

otidids
plural of otidid

outcrosser
An outcrossing species

outcrossers
plural of outcrosser

oviscape
The basal part of the ovipositor of some species of insects, typically the non-retractile sheath that remains exposed when the ovipositor is withdrawn and not in action.
The oviscapte or ovipositor.

oviscapes
plural of oviscape

ovococci
plural of ovococcus

ovococcus
An ellipsoid-shaped bacterium

oxacilinase
Misspelling of oxacillinase.

oxacillinase
Any of the OXA group of beta-lactamases, found mainly in Acinetobacter species.

oxacillinases
plural of oxacillinase

oxyphotobacteria
plural of oxyphotobacterium

oxyphotobacterium
Any photobacterium, of the class Oxyphotobacteria, that produces oxygen

oxyregulator
Any organism that can achieve oxyregulation

oxyregulators
plural of oxyregulator

oxyruncid
Any sharpbill in the family Oxyruncidae.

oxyruncids
plural of oxyruncid

oxytrichid
Any ciliate of the family Oxytrichidae

oxytrichids
plural of oxytrichid

ozarkodinid
Any conodont of the order †Ozarkodinida.

pachycephalid
Any of the Pachycephalidae.

pachycephalids
plural of pachycephalid

pachydiscid
Any in the family Pachydiscidae of extinct ammonites.

pachydiscids
plural of pachydiscid

padloper
Any of the genus Homopus of tiny tortoises, indigenous and endemic to southern Africa.

padlopers
plural of padloper

paedomorphocline
A sequence of increasingly more paedomorphic species

paedomorphoclines
plural of paedomorphocline

paenimyxin
A lipopeptide biopesticide produced by the bacterium Paenibacillus.

pagophile
Any organism preferring an icy habitat.

pagophiles
plural of pagophile

palaeoethology
Alternative form of paleoethology.

palaeontinid
Any cicadomorph in the family Palaeontinidae.

palaeontinids
plural of palaeontinid

palaeospecies
Alternative form of paleospecies.

palaeosubspecies
Alternative form of paleosubspecies.

palak
Spinach or similar greens (including Amaranthus species and Chenopodium album).

paleoethology
The study of the behaviour of extinct species of humans.
The study of behavior of organisms in the fossil record.

paleome
The genome of an extinct species

paleomes
plural of paleome

paleospecies
A species that is derived from the paleontological record; chronospecies.

paleosubspecies
A paleospecies that is considered a subspecies of an existing species, usually considered the immediate ancestor of the existing species.

paliguanid
Any lepidosauromorph in the family Paliguanidae.

paliguanids
plural of paliguanid

pallisander
a dense, heavy wood, similar to teak or mahogany, mostly from species of Dalbergia and Pterocarpus, as well as Machaerium

pallisanders
plural of pallisander

palmatolepid
Any conodont of the family †Palmatolepidae.

palynivore
Any organism that feeds on pollen; a pollinivore.

palynivores
plural of palynivore

pandeid
Any hydrozoan in the family Pandeidae.

pandeids
plural of pandeid

pandorid
Any pf the family Pandoridae of clams.

pandorids
plural of pandorid

panorpid
Any in the family Panorpidae of scorpionflies.

panorpids
plural of panorpid

panorpodid
Any scorpionfly in the family Panorpodidae.

panorpodids
plural of panorpodid

panortholog
An ortholog that is conserved throughout a genome.

panorthologs
plural of panortholog