English Words: O

15,494 words · Page 30 of 310

octalnoun

The number system that uses the eight digits 0, 1, 2, 3, 4, 5, 6, 7.

octaleadnoun

Eight atoms of lead in a chemical compound.

octaloguenoun

A series of eight statements.

octalogynoun

A set of eight works of art that are connected, and that can be seen either as a single work or as eight individual works. They are commonly found in literature, film, or video games.

octaloopnoun

An eight-base hairpin loop motif

octamanganesenoun

Eight manganese atoms or cations in a molecule (Mn₈)

octamernoun

An oligomer having eight subunits.

octamericadj

Of or pertaining to an octamer.

octamerizationnoun

oligomerization that forms an octamer

octamerousadj

Having parts in groups of eight

octameternoun

A line of verse containing eight metrical feet

octamethylnoun

(in combination) eight methyl groups in a molecule

octamethylenenoun

Eight methylene groups in a molecule (typically in a row, with substituents or functional groups at each end)

octamethylpyrophosphoramidenoun

An odorless organophosphate insecticide, C₈H₂₄N₄O₃P₂, that has also been used to treat myasthenia gravis.

octanalnoun

The saturated aliphatic aldehyde having eight carbon atoms

octanamidenoun

The acid amide of octanoic acid, CH₃CH₂CH₂CH₂CH₂CH₂CH₂CONH₂

octandrousadj

Having eight stamens.

octanenoun

Any of the eighteen isomeric aliphatic hydrocarbons (C₈H₁₈) found in petroleum, especially an iso-octane 2,2,4 trimethyl-pentane; they are used as fuels and solvents.

octanedionenoun

Any of several isomeric diketones, derived from octane, that are used as intermediates in organic synthesis

octanglenoun

A geometric figure with eight corners, an octagon.

octangularadj

Octagonal, with eight angles.

octangularlyadv

In an octangular manner.

octanitridenoun

Any nitride containing eight atoms of nitrogen

octanitrocubanenoun

A high explosive derived from cubane, and one of the most powerful chemical explosives known.

octanoatenoun

Any salt or ester of octanoic acid.

octanoicadj

Of or pertaining to octanoic acid or its derivatives

octanolysisnoun

alcoholysis using octanol

octanonenoun

Any aliphatic ketone that has eight carbon atoms

octanoylatedadj

reacted with octanoic acid

octanoylationnoun

reaction with octanoic acid (to form an octanoate)

octanoylcarnitinenoun

The N-octanoyl derivative of carnitine

Octansname

A small circumpolar constellation of the southern sky, said to resemble an octant. It lies closest to the southern celestial pole of any constellation.

octantnoun

The eighth part of a circle; an arc of 45 degrees.

octantaladj

Relating to an octant.

octantimonidenoun

Eight antimonide ions in a molecule (Sb₈)

octanucleotidenoun

A codon containing eight nucleotides.

octaosenoun

Any oligosaccharide containing eight monosaccharide moieties

octaoxidenoun

Alternative form of octoxide.

octaoxonoun

A chemical compound with eight oxygen atoms with double bonds.

octaoxygennoun

A red allotrope of oxygen, O₈, that is stable only under very high pressures

octapalladiumnoun

Eight palladium atoms or cations in a molecule (Pd₈)

octapartiteadj

divided into eight parts

octapeptidenoun

An oligopeptide having eight amino acids.

octaphosphorusnoun

eight atoms of phosphorus in a compound

Octaplaname

A Biblical octapla: an edition of the Bible in eight parallel versions or languages.

octaplesnoun

Synonym of octapla.

octapodynoun

A metre or verse of eight feet.

octapolaradj

That employs eight electrodes

octaprenylnoun

Formed from eight isoprene units

octaquanoun

Eight water molecules in a compound.

Spelling & Dictionary Insight

The English alphabetical index for the letter O contains 15,494 headwords drawn from our Wiktionary-derived dictionary table. At 50 entries per page the browse splits into 310 pages, and you are currently viewing page 30. Every row above is a dictionary-backed entry with a canonical slug, and each links through to a full definition page with pronunciation, senses, etymology, and related-word data where available.

On this page 50 of 50 entries carry a part-of-speech tag and 50 carry at least one stored definition. Coverage varies across letters because Wiktionary volunteers build entries at different speeds for different parts of the alphabet, letters with common starting sounds (S, C, T, P) usually have the densest coverage, while less frequent starters (X, Q, Z) tend to have shorter but more specialised lists. PlainSpell surfaces whatever data is present and links back to the source when a definition is not yet recorded.

For readers using this index as a spelling reference, the guarantee is that every form you see on the list is a documented English headword, not a guess, not a derived inflection lacking a lemma row. If a word you expected to find is absent from the "O" list, it usually means the form exists only as an inflection of another lemma (e.g. a past participle stored under the infinitive) or the entry has not yet been imported from Wiktionary. Use the search bar or the misspelling lookup to resolve these cases.