All articles starting with O
9,097 articles
Ouyang Zi
Ouyang Zi (歐陽子), pen name of Hong Zhihui, is a Taiwanese writer born in 1939, known for psychologically intense 1960s short fiction and for co-founding the magazine Modern Literature.
Ouyang Ziyuan
Ouyang Ziyuan (欧阳自远, born 1935) is a Chinese geochemist and cosmochemist, the first chief scientist of China's Chang'e lunar exploration program, known as the "Father of Chang'e".
Ouyeel
Ouyeel, formally Ouyeel Cloud Business Co. (欧冶云商), is a Chinese steel industry internet platform founded in 2015 by China Baowu Steel Group, integrating steel trading, logistics, and processing services.
Ouyi Zhixu
Ouyi Zhixu (蕅益智旭, 1599–1655) was a Chinese Buddhist monk and prolific writer of the late Ming, one of its four great monks and later honored as the ninth patriarch of the Pure Land school.
Ouzo
Ouzo (ούζο) is a Greek anise-flavored distilled spirit, legally a "distilled anis", produced exclusively in Greece and Cyprus, minimum 37.5% vol, at least 20% distillate, that turns milky with water (the ouzo effect).
Ouzo effect
The ouzo effect, also called the louche effect, is the formation of a milky oil-in-water emulsion when water is added to anise-flavored spirits such as ouzo and pastis.
Ouzounboudjak Biosphere Reserve
Ouzounboudjak (Uzunbudzhak, Узунбуджак) is a UNESCO biosphere reserve in Bulgaria's Strandzha mountain, first designated 1977 and re-approved 2017, covering Malko Tarnovo municipality with core, buffer, and transition zones.
Ov Sulfur
Ov Sulfur is a Las Vegas blackened deathcore band formed in 2020 by ex-Suffokate vocalist Ricky Hoover. Signed to Century Media, it released The Burden Ov Faith (2023) and Endless (2026), blending symphonic and black metal elements with anti-religious lyrics.
Ovadia Yosef (עובדיה יוסף)
Ovadia Yosef, known to followers as Maran, was an Iraqi-born Israeli rabbi who served as Sephardi Chief Rabbi of Israel from 1972 to 1983 and founded the Shas party.
Ovako
Ovako is a Stockholm-headquartered European producer of engineering and bearing steel in bar, tube, ring, and wire, a subsidiary of Sanyo Special Steel since 2019.
Ovako Metals Oy Ab
Ovako Metals Oy Ab was a Finnish steel and metals distribution company headquartered in Tampere, serving engineering and construction customers in Finland and the Baltic countries until 2026.
Oval
An oval is a closed plane curve resembling the outline of an egg or an ellipse; unlike the ellipse, it has no single precise mathematical definition in ordinary usage.
Oval Office
The Oval Office is the US president's formal West Wing office, first used by William Howard Taft in October 1909, designed by Nathan C. Wyeth, moved to its southeast-corner location by Franklin Roosevelt in 1934.
Oval Office Swedish ivy
Oval Office Swedish ivy: Plectranthus verticillatus, a South African mint-family trailer displayed on the White House Oval Office mantel from the Kennedy era until February 2025, now surviving through staffer cuttings.
Oval track racing
Oval track racing: closed-circuit motor racing on banked left-turn ovals (Daytona, Talladega, Indianapolis), run counterclockwise, spanning NASCAR stock cars, IndyCar, sprint cars, and dirt short tracks, distinct from road and street course racing.
Ovaltine
Ovaltine (Ovomaltine) is a Swiss malted milk drink powder created by Albert Wander in Bern, launched in 1904, sold in pharmacies before becoming a breakfast drink; ABF owns it worldwide except the US, where Nestle holds the trademark.
Ovarian cancer
Ovarian cancer is a cancer in which malignant cells form in the ovaries, fallopian tubes, or peritoneum. It is the leading cause of death among gynecologic cancers.
Ovarian carcinoma immunoreactive antigen domain
The OCIA (ovarian carcinoma immunoreactive antigen) domain, Pfam PF07051, is a conserved N-terminal protein domain in OCIAD1/Asrij and OCIAD2, arising by tandem duplication 435-500 mya, mediating endosomal localization and STAT3 activation.
Ovarian cyst
An ovarian cyst is a fluid-filled sac that develops in or on an ovary. Cysts are very common, and most are benign and resolve without treatment.
Ovarian cystectomy
Ovarian cystectomy is a gynecological operation that removes an ovarian cyst while leaving a functional ovary, most often done laparoscopically for endometriomas, dermoid cysts, and cystadenomas.
Ovarian drilling
Ovarian drilling (laparoscopic ovarian drilling, LOD; transvaginal TVOD/UTND) is a second-line surgical ovulation-induction treatment for clomiphene-resistant PCOS, using diathermy, laser, or needle punctures of the ovaries, restoring ovulation in most treated women.
Ovarian dysfunction
Ovarian dysfunction (ICD-10 E28; ICD-11 5A80) covers ovarian hormone and ovulation disorders, including PCOS, androgen excess, and primary ovarian insufficiency before age 40, diagnosed with FSH, AMH, and ultrasound.
Ovarian dysgerminoma
Ovarian dysgerminoma is a rare malignant ovarian tumor arising from primordial germ cells, the most common malignant ovarian germ cell tumor, affecting mainly young women with a good prognosis.
Ovarian fibroma
Ovarian fibroma (fibroma of ovary, ORPHA:314473) is a rare benign sex cord-stromal ovarian tumor of spindle cells and collagen, the most common benign solid ovarian tumor (1-4% of benign ovarian tumors); Meigs syndrome with ascites and pleural effusion occurs in about 1%.
Ovarian fibrothecoma
Ovarian fibrothecoma, a rare benign sex cord-stromal ovarian tumor mixing fibroma and thecoma features, typically unilateral in perimenopausal and postmenopausal women, sometimes with estrogenic effects, ascites, elevated CA-125, or Meigs syndrome.
Ovarian follicle
Ovarian follicle: the ovary's basic unit, an oocyte with granulosa and theca cells. Stages run primordial to preovulatory (Graafian); NICHD recognizes six preantral and five antral stages; only ~500 follicles ovulate in a lifetime.
Ovarian Function Tests
Ovarian function tests, or ovarian reserve tests (AMH, antral follicle count, basal FSH/estradiol), estimate remaining egg quantity; they predict IVF oocyte yield but not fertility independently of age.
Ovarian hyperstimulation
Ovarian hyperstimulation, also called controlled ovarian stimulation, uses injectable gonadotropins to grow multiple follicles in one IVF cycle, with ovarian hyperstimulation syndrome as its main risk.
Ovarian hyperstimulation syndrome
Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of IVF ovarian stimulation, marked by ovarian enlargement, VEGF-driven fluid shift, ascites, and hemoconcentration; mild in 20-33% of cycles, severe in 3-8%.
Ovarian pregnancy
Ovarian pregnancy (ovarian ectopic pregnancy, ICD-11 JA01.2) is a rare ectopic pregnancy implanted in the ovary, defined by Spiegelberg's criteria, presenting with pain and hemoperitoneum, and usually treated by laparoscopic ovarian-sparing surgery.