operably
Such that it allows an operation to take place.

operantly
In an operant manner

operatically
In an operatic manner.

operationally
In an operational manner; in accordance with an operation.

operatively
In an operative manner.

opercularly
In opercular fashion.

operonically
In an operonic manner

operosely
In an operose manner.

ophitically
In an ophitic manner.

ophthalmically
In an ophthalmic manner

ophthalmodynamometrically
In terms of, or by means of, ophthalmodynamometry.

ophthalmologically
In an ophthalmological manner
With reference to, or by means of ophthalmology.

ophthalmoscopically
By means of ophthalmoscopy.

opinatively
In an opinative manner.

opiniatively
Archaic form of opinionatively.

opinionatedly
In an opinionated manner.

opinionately
In a conceited manner.

opinionatively
In an opinionative manner.

opportunely
In a manner suitable for some particular purpose.
In a manner convenient or advantageous at some particular time.

opportunistically
In an opportunistic manner.

opposably
in an opposable manner

opposedly
In an opposed manner

opposingly
in a manner that opposes

oppositely
In an opposite manner.

oppositionally
In terms of, or by means of, opposition.

oppositively
In an oppositive manner.

oppressingly
So as to oppress; with or by means of oppression; oppressively.

oppressively
In an oppressive manner.

opprobriously
In an opprobrious manner.

optatively
In an optative way.

optically
regarding or using optics

optimally
In an optimal manner.

optimistically
In an optimistic manner.

optionally
In an optional manner; not mandatorily.

optoacoustically
In an optoacoustic way.

optoelectrically
In an optoelectric manner

optoelectronically
By means of optoelectronics

optogenetically
In an optogenetic manner

optokinetically
In an optokinetic manner

optomechanically
By means of, or in terms of, optomechanics.

optometrically
In an optometric way.

opulently
In an opulent manner.

oracally
Synonym of oracularly.

oracularly
In an oracular manner.

oraculously
In an oraculous manner; like an oracle.

orally
By mouth.
Spoken as opposed to written.

orangely
In an orange manner.

oratorially
In an oratorial way.

oratorically
In an oratorical manner.

orbicularly
In an orbicular fashion.

orbiculately
In an orbiculate manner.

orbitally
By means of or in relation to orbit
By means of or in relation to an orbital or orbitals

orchestrally
In an orchestral manner.

ordinally
In an ordinal manner.

ordinarily
In accordance with normal custom or routine; as a matter of established occurrence.
Usually or as a general rule; commonly.
In the usual manner; unexceptionally.

ordinately
In an ordinate manner; regular; orderly.

ordoliberally
In an ordoliberal manner.

oreddy
Pronunciation spelling of already, representing Singapore English.

orfen
Pronunciation spelling of often, representing British English.

organically
In an organic manner.
In the manner of a living organism.
As part of an organized whole.
Inherently, naturally or constitutionally.
From, or using organic matter.
With regard to organic husbandry.

organisationally
Alternative spelling of organizationally.

organismically
like an organism; in relation to an organism; at an organismic level

organizationally
In an organizational manner.
With regard to organization or an organization.

organizedly
In an organized manner.

organoautotrophically
In an organoautotrophic manner

organocatalytically
Of or pertaining to organocatalysis.

organogenetically
In an organogenetic manner.

organoheterotrophically
In an organoheterotrophic manner

organoleptically
In an organoleptic manner.

organotrophically
By means of organotrophy

organotropically
In an organotropic manner.

organotypically
In an organotypic manner

orgasmically
In an orgasmic way.

orgastically
In an orgastic sense; as regards sexual orgasm.

orgiastically
In an orgiastic fashion.

orgulously
In an orgulous manner.

orientally
In an oriental manner.

orientationally
With regard to orientation

oriently
In an orient manner.

origamically
By means of origami.

originalistically
In an originalistic manner.

originally
As it was in the beginning; at first.
In an original manner.

originarily
In an originary manner.

originatively
In an originative manner.

orl
An alder tree.
orl fly

orls
plural of orl

ornamentally
In an ornamental way.

ornately
In an ornate manner.

ornerily
In an ornery manner.

ornithologically
In terms of ornithology.

orofaecally
Alternative form of orofecally.

orofecally
By the orofecal route.

orogastrically
By means of, or with reference to the mouth and the stomach

orogenically
In terms of, or by means of, orogeny.

orographically
In terms of or by means of orography.

orologically
In terms of orology.

oromucosally
In an oromucosal manner

oronasally
In an oronasal manner

oropharyngeally
In an oropharyngeal manner

orotracheally
In an orotracheal manner

orotundly
In an orotund manner.

orpedly
Boldly; bravely; stoutly.

orthodiagraphically
By means of orthodiagraphy.

orthodontically
By orthodontic means.

orthodoxally
Obsolete form of orthodoxly.

orthodoxically
In an orthodoxical manner.

orthodoxly
In a correct or proper way; conventionally; correctly.
In a religiously orthodox way; in accordance with accepted religious doctrine.

orthodromically
In an orthodromic manner

orthoepically
In an orthoepical manner: pronounced correctly or in accordance with standard usage.

orthogenetically
In terms of, or by means of, orthogenesis.

orthogonally
In an orthogonal manner; perpendicularly; at right angles

orthogradely
In an orthograde manner.

orthographically
Regarding or relating to orthography (the way in which languages, usually natural languages, are written).
According to standardized or formally accepted orthography: using proper spelling, and (more strictly) proper spelling, punctuation, capitalization, and italics.
Using an orthographic projection (a way of showing three-dimensional objects in two-dimensional engineering drawings).

orthologously
In regard to, or by means of orthology

orthometrically
In an orthometric manner.

orthonasally
In an orthonasal manner

orthonormally
In an orthonormal manner

orthopaedically
Alternative form of orthopedically.

orthopalinally
In an orthopalinal manner

orthopantomographically
By means of orthopantomography.

orthopedically
In an orthopedic manner.

orthophotographically
In terms of, or by means of, orthophotography.

orthopically
In an orthopic manner.

orthopraxically
In an orthopraxical fashion.

orthopterologically
In terms of orthopterology.

orthoptopically
Misspelling of orthotopically.

orthoradially
In an orthoradial manner.

orthorhombically
In an orthorhombic manner

orthosterically
In an orthosteric manner

orthotactically
In terms of orthotactics.

orthotopically
In an orthotopic manner.

orthotropically
In an orthotropic manner.

orthotropously
In an orthotropous manner.

ortotopically
Misspelling of orthotopically.

oryctognostically
In a manner relating to oryctognosy.

oryctographically
In a manner relating to oryctography.

oscillatingly
In an oscillating way or manner.

oscillationally
In terms of oscillation.

oscillatively
In an oscillative manner.

oscillatorily
In a way of oscillations or oscillators.

oscillographically
By means of oscillography.

oscillometrically
In an oscillometric manner

oscitantly
In an oscitant manner; drowsily or yawningly

oscularly
By means of the mouth.

osmometrically
In terms of, or by means of, osmometry.

osmoregulatorily
In terms of, or by means of, osmoregulation.

osmotically
In an osmotic manner
With regard to osmosis

osmotrophically
In an osmotrophic manner

osseously
By means of bone.

ostensibly
Seemingly, apparently, on the surface; supposedly, according to representations or implications made by someone (especially when their motives are suspected by others).

ostensively
In an ostensive manner.
Ostensibly.