obsessive-compulsive disorder An anxiety disorder that is characterized by obsessive thoughts and compulsive actions. Abbreviated OCD. The obsessive thoughts are unwanted ideas or impulses that repeatedly well up in the mind of the person with OCD. These thoughts are intrusive and unpleasant, and they produce a high degree of anxiety. In response to their obsessions,…
observer variation Failure by the observer in a study or test to measure accurately, resulting in error. Inter-observer variation is the amount of variation between the results obtained by two or more observers examining the same material. Intraobserver variation is the amount of variation one observer experiences when observing the same material more than once.
OB/GYN 1 Obstetrician/gynecologist. 2 Obstetrics and Gynecology
obesity-related disease A disease for which obesity is a significant risk factor. Obesity increases the risk of developing a number of diseases, and it can be a diagnostic marker for others. Diseases related to obesity include type 2 diabetes; high blood pressure (hypertension); stroke (cerebrovascular accident); heart attack (myocardial infarction); heart failure (congestive heart failure);…
obesity, gynecoid A state of being overweight with fat distribution in a pattern that is generally characteristic of a woman, with the largest amount around the hips and thighs.
obesity The state of being well above one’s normal weight. A person has traditionally been considered to be obese if they are more than 20 percent over their ideal weight. Obesity has been more precisely defined as having a body mass index (BMI) of 30 and above. The cause of obesity is often multifactorial, based…
Oath of Maimonides See Daily Prayer of a Physician.
oat-cell lung cancer See small-cell lung cancer.
nystagmus Rapid, rhythmic, repetitious, and involuntary eye movements. Nystagmus can be horizontal, vertical, or rotary. Whatever form it takes, nystagmus is an abnormal eye finding and a sign of disease within the eye or the nervous system.
nymph A stage in the life cycle of certain arthropods, such as ticks and lice. The nymph stage is between the nit and the adult louse stages. A nymph louse looks like an adult but is smaller. Nymphs mature into adults about 7 days after hatching. To live, the nymph must feed on blood.
nyctophobia Pathological fear of the dark.
nyctanopia Impaired vision in dim light and in the dark, due to impaired function of the rods in the retina. Nyctanopia is a classic finding with vitamin A deficiency. Also known as day sight, nocturnal amblyopia, and nyctalopia.