ocypodid
Any crab in the family Ocypodidae.

ocypodids
plural of ocypodid

odiniid
Any fly of the family Odiniidae.

odiniids
plural of odiniid

odonate
Any carnivorous insect of the order Odonata; a dragonfly or damselfly.

odonates
plural of odonate

odontaspidid
Any shark in the family Odontaspididae.

odontaspidids
plural of odontaspidid

odontobutid
Any fish in the family Odontobutidae.

odontobutids
plural of odontobutid

odontodactylid
Any mantis shrimp in the family Odontodactylidae (Odontodactylus spp.).

odontodactylids
plural of odontodactylid

odontomach
Any ant of the genus Odontomachus.

odontophrynid
Any frog of the family Odontophrynidae

odontophrynids
plural of odontophrynid

odontopterygian
An extinct pelican-like pelagornithid seabird of the suborder Odontopterygia.

odontopterygians
plural of odontopterygian

odostome
Any sea snail of the genus Odostomia

odostomes
plural of odostome

odostomiid
Any sea snail in the family Odostomiidae, now considered to be the pyramidellid subfamily Odostomiinae.

odostomiids
plural of odostomiid

oecobiid
Any spider in the family Oecobiidae.

oecobiids
plural of oecobiid

oedemerid
Any beetle in the family Oedemeridae.

oedemerids
plural of oedemerid

oedicerotid
Any amphipod in the family Oedicerotidae.

oedicerotids
plural of oedicerotid

oithonid
Any copepod of the family Oithonidae

oithonids
plural of oithonid

oldfieldthomasiid
Any notoungulate mammal in the family Oldfieldthomasiidae.

oldfieldthomasiids
plural of oldfieldthomasiid

oleacinid
Any snail in the family Oleacinidae.

oleacinids
plural of oleacinid

olethreutid
Any moth in the family Olethreutidae, now considered to be the tortricid subfamily Olethreutinae

olethreutids
plural of olethreutid

olethreutine
Any moth of the tribe Olethreutini

olethreutines
plural of olethreutine

oligoneurid
Any mayfly of the family Oligoneuridae

oligoneurids
plural of oligoneurid

oligoneuriid
Any mayfly of the family Oligoneuriidae

oligoneuriids
plural of oligoneuriid

oligopithecid
Any extinct monkey in the family Oligopithecidae.

oligopithecids
plural of oligopithecid

olivellid
Any sea snail in the family Olivellidae, now considered to be part of the family Olividae.

olivellids
plural of olivellid

olivid
Any sea snail in the family Olividae.

olivids
plural of olivid

ologamasid
Any mite in the family Ologamasidae.

ologamasids
plural of ologamasid

olyrid
Any catfish in the family Olyridae, which may be a synonym for the Bagridae.

olyrids
plural of olyrid

ommatid
Any beetle in the family Ommatidae.

ommatids
plural of ommatid

omomyine
Any extinct primate of the clade †Omomyinae

omomyines
plural of omomyine

omphalotrochid
Any extinct gastropod in the family Omphalotrochidae.

omphalotrochids
plural of omphalotrochid

omul
Any of the salmon-like fish of species Coregonus migratorius (syn. Coregonus autumnalis migratorius), native to Lake Baikal in Siberia

omuls
plural of omul

oncaeid
Any copepod in the family Oncaeidae.

oncaeids
plural of oncaeid

onchocercid
Any nematode in the family Onchocercidae.

onchocercids
plural of onchocercid

oncoceratid
Any extinct nautiloid cephalopod in the family Oncoceratidae.

oncoceratids
plural of oncoceratid

oncomice
plural of oncomouse

oncomouse
A type of laboratory mouse that has been genetically modified to carry an activated oncogene, increasing its susceptibility to cancer.

onuphid
Any polychaete worm of the family Onuphidae.

onuphids
plural of onuphid

onychochilid
Any extinct gastropod in the family Onychochilidae.

onychochilids
plural of onychochilid

onychodont
Synonym of onychodontid.

onychodontid
Any extinct fish the family Onychodontidae

onychodontids
plural of onychodontid

onychodonts
plural of onychodont

oolacunta
An extinct marsupial, the desert rat kangaroo (Caloprymnus campestris), that lived in a sand-ridge and gibber-plain habitat in south-western Queensland and north-eastern Australia.

oolacuntas
plural of oolacunta

oonopid
Any spider in the family Oonopidae.

oonopids
plural of oonopid

opabiniid
Any extinct arthropod in the family Opabiniidae.

opabiniids
plural of opabiniid

openbill
Either of two species of bird in the genus Anastomus of the stork family Ciconiidae, with a distinctive gap between the mandibles of the closed bill.

openbills
plural of openbill

opheliid
Any polychaete worm of the family Opheliidae.

opheliids
plural of opheliid

ophidiiform
Any ray-finned fish of the order Ophidiiformes

ophiocistioid
Any echinoderm of the class †Ophiocistioidea.

ophiopsid
Any extinct fish of the family Ophiopsidae

ophiopsids
plural of ophiopsid

ophiruoid
Misspelling of ophiuroid.

ophiure
Any echinoderm of the class Ophiuroidea

ophiures
plural of ophiure

ophiuroid
An echinoderm of the class Ophiuroidea; the brittlestar.

ophiuroids
plural of ophiuroid

opiine
A braconid wasp of the subfamily Opiinae

opiines
plural of opiine

opilioacarid
Any mite in the family Opilioacaridae.

opilioacarids
plural of opilioacarid

opisthodontian
Any moth of the genus Opisthodontia
Any extinct rhynchocephalian of the clade Opisthodontia

opisthodontians
plural of opisthodontian

opisthoproctid
Any fish in the family Opisthoproctidae; a barreleye.

opisthoproctids
plural of opisthoproctid

opisthorchiid
Any trematode flatworm in the family Opisthorchiidae.

opisthorchiids
plural of opisthorchiid

opisthoteuthid
Any octopus in the family Opisthoteuthidae.

opisthoteuthids
plural of opisthoteuthid

oplegnathid
Any fish in the family Oplegnathidae.

oplegnathids
plural of oplegnathid

oplophorid
Any shrimp in the family Oplophoridae.

oplophorids
plural of oplophorid

opomyzid
Any fly of the family Opomyzidae.

opomyzids
plural of opomyzid

opostegid
Any moth in the family Opostegidae.

opostegids
plural of opostegid

orangeworm
A snout moth of the genus Amyelois that is a pest to some commercial crops

orangeworms
plural of orangeworm

orbiniid
Any polychaete worm of the family Orbiniidae.

orbiniids
plural of orbiniid

orbitestellid
Any sea snail in the family Orbitestellidae.

orbitestellids
plural of orbitestellid

orbweaver
Any spider of the family Araneidae.

orculid
Any snail in the family Orculidae.

orculids
plural of orculid

orectolobid
Any shark in the family Orectolobidae.

orectolobids
plural of orectolobid

oreohelicid
Any snail in the family Oreohelicidae.

oreohelicids
plural of oreohelicid

oreosomatid
Any fish in the family Oreosomatidae.

oreosomatids
plural of oreosomatid

oriolid
Any bird in the family Oriolidae.

oriolids
plural of oriolid

oriostomatid
Any extinct sea snail in the family Oriostomatidae.

oriostomatids
plural of oriostomatid

ormyrid
Any wasp in the family Ormyridae.

ormyrids
plural of ormyrid

orneodid
Any moth in the family Orneodidae, a synonym of the Alucitidae.

orneodids
plural of orneodid

ornithoidichnite
A fossil track resembling that of a bird.

ornitholite
The fossil remains of a bird.
A stone of various colours bearing the figures of birds.

ornitholites
plural of ornitholite

ornithorhynchid
A duck-billed platypus, or any of its extinct relatives in the family Ornithorhynchidae.

ornithorhynchids
plural of ornithorhynchid

orodontid
Any extinct cartilaginous fish in the family Orodontidae.

orodontids
plural of orodontid

orsolobid
Any spider in the family Orsolobidae.

orsolobids
plural of orsolobid

ortalid
A fly of the family Ortalidae (now Ulidiidae).

ortalids
plural of ortalid

orthagan
Any pyralid moth of the genus Orthaga.

orthagans
plural of orthagan

ortheziid
Any scale insect of the family Ortheziidae.

ortheziids
plural of ortheziid

orthoceratoid
Any extinct cephalopod of the subclass †Orthoceratoidea

orthoceratoids
plural of orthoceratoid

orthoteliine
Any moth of the subfamily Orthoteliinae

orthoteliines
plural of orthoteliine

orussid
Any wasp of the family Orussidae.

orussids
plural of orussid

orvet
The slowworm.

orvets
plural of orvet

osteichthian
Misspelling of osteichthyan.