Sexual Dictionary - letter O

Obstetrics
branch of medicine that deals with the care of women during pregnancy, labor, and the recuperative period following delivery.
Oligomenorrhea
fewer (less than 8 cycles per year or coming less frequently than every 35 days), infrequent or light menstruation. It is quite common for women at the beginning of their reproductive lives - due to imperfect coordination between the hypothalamus, the pituitary gland, and the ovaries (true oligomenorrhea can not occur until menstrual periods have been established by age 16), or for women at end of their reproductive lives - due to the hormonal imbalance, when regular ovulation does not occur. Also can be caused by anorexia nervosa, because the ratio of body fat to weight drops too low, polycystic ovarian syndrome, emotional stress or chronic illness.
Oligospermia
a spermatozoa concentration in the semen of less than 20 million per cc. A sperm count low enough to cause a fertility problem.
Onanism
another term for masturbation.
Oncology
branch of medicine devoted to diagnosis and treatment of cancer. The specialist is called oncologist.
Oophorectomy
surgical removal of one or both ovaries. It may be performed to remove tumor, to treat endometriosis, in case of cancer, or to stop the production of estrogen in order to reduce the risk of breast cancer. It is a form of sterilization.
Opium
a narcotic drug which is extracted from the unripe seed pods of the opium poppy. Opium can be highly addictive.
Opportunistic infections
infections that would normally not happen, but that do because the immune system is weakened and cannot fight them. Opportunistic infections include :
  • Bacterial Infections
    • Mycobacterium Avium Complex
    • Salmonellosis
    • Syphilis & Neurosyphilis
    • Tuberculosis
  • Viral Infections
    • Cytomegalovirus
    • Herpes Simplex Virus
    • Varicella-Zoster virus
    • Hepatitis
    • Epstein-Barr virus
    • Ano-genital Warts
    • Molluscum Contagiosum
  • Fungal Infections
    • Candidiasis
    • Cryptococcal Meningitis
    • Histoplasmosis
  • Parasitic infections
    • Toxoplasmosis
    • Pneumonias
  • Cancers
  • Neurological Conditions
Orchiectomy
surgical removal of one or both testicles. Performed in order to prevent or cure cancer or as a sex change opperation. When only one testicle is removed, there is no effect on male hormone production, sexual function or fertility.
Orchitis
inflammation of one or both of the testes, often occurring as a result of mumps or other infection, trauma, or cancer.
Oral contraceptive
a contraceptive in the form of a pill containing estrogen and progestin to inhibit ovulation and so prevent pregnancy.
See also birth control methods.
Oral sex
human sexual behavior involving contact between the tongue, lips or mouth and any other sexual organ. The contact between mouth and vagina is called cunnilingus, the contact between mouth and penis is called fellatio and the contact between mouth and anus is called annilingus.
Orchitis
inflammation of one or both of the testes, often occurring as a result of mumps or other infection, trauma, or cancer.
Orgasm
the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure. Orgasm is accompanied by quick cycles of muscle contraction in the lower pelvic muscles, which surround the primary sexual organs and the anus. Orgasms are often associated with other involuntary actions, including muscular spasms in multiple areas of the body. Orgasm is experienced by both males and females.
Also called sexual climax.
Orgasmic platform
the vasocongestion and the pubococcygeal muscle contractions that occurs in the outer third of the vagina during woman sexual arousal. Results in the reducing the diameter of the opening of the vagina, simultaneous contractions of the anal sphincter, rectum, and perineum forming the orgasmic reflex.
Orgy
simultaneous sexual activity among more than two people.
Also called group sex.
Osteoporosis
a progressive condition that is characterized by a decrease in bone mass and density, causing bones to become fragile. Bone mass is greatest in the young, and declines with age, particularly in women after the menopause.
Outercourse
sexual stimulation or activity between partners that does not involve anal or vaginal penetration or exchange of bodily fluids. Considered a practice of safer sex. See also sexual behavior.
Ovarian follicle
small, fluid-filled structure in which the eggs develop. At ovulation, the follicle bursts open, releasing the egg into the fallopian tube. After release of the egg, the follicle is known as the corpus luteum. Ovarian follicle is also called Graafian follicle.
See also follicle.
Ovaries
the pair of female reproductive glands in which the eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus. Ovaries also produce female sex hormones - estrogen and progesterone.
Ovulation
the release of a mature egg from its ovarian follicle. It usually occurs with approximately day 14 before the start af a new menstrual cycle. Ovulation is the time around when a woman is most likely to conceive.
Ovum
see egg.