English Words: O

15,494 words · Page 32 of 310

octenylnoun

Any of several isomeric radicals derived from an octene

octeractnoun

An eight-dimensional hypercube

octetnoun

A group or set of eight of something.

octetoniumnoun

A color singlet bound state of color-octet scalars.

octettenoun

Rare spelling of octet.

octicadj

Of the eighth degree or order.

octilinearadj

Composed of horizontal, vertical and/or diagonal (45 degrees) line segments only

octillionnum

A thousand trillion trillion, a billion billion billion: 1 followed by 27 zeros, 10²⁷.

octillionairenoun

Somebody whose wealth is at least one octillion (10²⁷) currency units.

octillionfoldadj

By a multiple of one octillion; by an octillion times as much or as many.

octillionthadj

The ordinal form of the number octillion.

octinoxatenoun

The ester octyl methoxycinnamate when used as a sunscreen.

octisalatenoun

The ester octyl salicylate when used as a sunscreen.

Octlantisname

An area of Jervis Bay, New South Wales, Australia, where gloomy octopuses (Octopus tetricus) are known to congregate. A colony of octopi and their constructed dens built out of scallop shells.

octletnoun

A word (or rather, a doubleword) consisting of eight bytes (64 bits)

octlinoun

Pulque.

octonoun

An octopus (safety device).

octo-champnoun

Alternative spelling of octochamp.

octo-champsnoun

plural of octo-champ

octoadnoun

Synonym of ogdoad (“a thing made up of eight parts”).

octoalloynoun

An alloy of eight metals (gold, silver, copper, lead, zinc, tin, iron, and antimony or mercury), formerly used in India for making idols.

octoatenoun

octanoate

octobassnoun

A very large bass requiring two musicians, one to finger and one to bow.

octobassistnoun

Someone who plays the octobass.

Octobername

The tenth month of the Gregorian calendar, following September and preceding November.

October 7name

The attacks against Israel by Hamas on October 7, 2023.

October 8th Jewnoun

A Jewish person who reconnected with their Jewish identity as a result of the Hamas-led attack on Israel on October 7, 2023.

October beernoun

A strong ale traditionally brewed in October.

October Revolutionname

The second of two revolutions which took place in Russia in 1917.

Octoberfestname

The Bavarian holiday (Oktoberfest or Wiesn), or any such holiday, celebrated in late September to early October, typically featuring German music, cuisine, and beer-drinking as prominent activities.

Octoberishadj

Resembling or characteristic of the month of October.

Octoberlyadj

Characteristic of the month of October.

Octobersname

plural of October

Octoberyadj

characteristic of the month of October

octobrachiateadj

Having eight brachia, arms, or rays.

Octobraladj

Characteristic of October

Octobristnoun

A member of the league formed October 1905 in response to imperial policies.

octocellularadj

Having eight cells.

octocentenarynoun

An eight-hundredth anniversary.

octochampnoun

A winner of eight consecutive heats of the British television game show Countdown.

octochampsnoun

plural of octochamp

octocontrabassnoun

An instrument that is pitched one octave below the contrabass.

octocopternoun

An unmanned rotorcraft having eight rotors.

octocoralnoun

An anthozoan of the subclass Alcyonaria, having eight-branched tentacles and eight septa.

octocoreadj

Composed of eight cores.

octocrylenenoun

An ester formed by the condensation of a diphenylcyanoacrylate with 2-ethylhexanol, used in sunscreens and cosmetics.

octodenoun

A thermionic valve that has eight electrodes or similar elements

octodecillionnum

10⁵⁷.

octodecimaladj

Having eight times ten faces.

octodecimonoun

A size of a sheet of paper resulting from folding and cutting a sheet of paper into eighteenths (3.5"–4.5" x 4.9"–5.9").

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 32. 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.