4-letter words containing o, i
- piro — piroplasmosis.
- piso — (in the Philippines) a peso
- poil — a yarn or thread made from silk, used for ribbon, velvet, and as the core of gold, silver, and tinsel yarn.
- pori — a seaport in W Finland, on the Gulf of Bothnia.
- rico — Racketeer Influenced and Corrupt Organizations Act: a U.S. law, enacted in 1970, allowing victims of organized crime to sue those responsible for punitive damages.
- riot — a noisy, violent public disorder caused by a group or crowd of persons, as by a crowd protesting against another group, a government policy, etc., in the streets.
- rivo — an informal toast or drinking cry
- rodi — Italian name of Rhodes.
- roil — to render (water, wine, etc.) turbid by stirring up sediment.
- roji — a Japanese tea garden or the path of stones which leads to the tea room
- roti — roast.
- sibo — SIxteen Bit Organisers
- sijo — a Korean lyric poem consisting of three lines
- silo — a structure, typically cylindrical, in which fodder or forage is kept.
- sion — a canton in SW Switzerland. 2021 sq. mi. (5235 sq. km). Capital: Sion.
- siop — (formerly) the secret and central U.S. contingency plan for waging a nuclear war with the Soviet Union.
- soif — Summary Object Interchange Format
- soil — the act or fact of soiling.
- soli — a musical composition or a passage or section in a musical composition written for performance by one singer or instrumentalist, with or without accompaniment: She sang a solo.
- sori — plural of sorus.
- thio — containing sulfur, especially in place of oxygen.
- tico — a native or inhabitant of Costa Rica.
- tiro — tyro.
- tiso — Josef [yaw-sef] /ˈyɔ sɛf/ (Show IPA), 1887–1947, Slovak Roman Catholic clergyman and politician.
- tito — Marshal (Josip Broz) 1891–1980, president of Yugoslavia 1953–80.
- toil — Usually, toils. a net or series of nets in which game known to be in the area is trapped or into which game outside of the area is driven.
- toit — to walk or move in an unsteady manner, as from old age
- toni — Anton [ahn-tohn] /ˈɑn toʊn/ (Show IPA), ("Toni") 1935–2009, Austrian skier.
- topi — topee.
- tori — plural of torus.
- trio — a musical composition for three voices or instruments.
- vico — Giovanni Battista [jaw-vahn-nee baht-tees-tah] /dʒɔˈvɑn ni bɑtˈtis tɑ/ (Show IPA), 1668–1744, Italian philosopher and jurist.
- vigo — Jean [zhahn] /ʒɑ̃/ (Show IPA), (Jean Almereyda) 1905–34, French film director.
- vino — wine; specifically, red Italian wine, as chianti.
- viol — a bowed musical instrument, differing from the violin in having deeper ribs, sloping shoulders, a greater number of strings, usually six, and frets: common in the 16th and 17th centuries in various sizes from the treble viol to the bass viol.
- viso — Mount, a mountain in NW Italy: highest peak of the Cottian Alps. 12,602 feet (3841 meters).
- vito — a male given name.
- vivo — with life and vigour
- void — Law. having no legal force or effect; not legally binding or enforceable.
- voip — Voice over IP
- voit — Carl or Karl von [kahrl fuh n] /kɑrl fən/ (Show IPA), 1831–1908, German physiologist.
- wiho — Womens Ice Hockey Organisation
- wino — a person who is addicted to wine, especially a derelict.
- wiol — Washington Interscholastic Orienteering League
- wipo — World Intellectual Property Organization
- wito — Women In The Outdoors
- xiao — Type of Chinese flute.
- yaoi — (slang, pornography, anime, manga) A form of hentai involving two or more males in a homosexual relationship, primarily intended for a female audience.
- yogi — a person who practices yoga.
- yoni — (in Shaktism) the external female genitals regarded as the symbol of Shakti. Compare lingam (def 2).