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(grōs) [L. grossus, thick] 1. Visible to the naked eye. 2. Consisting of large particles or components; coarse or large.


In histopathology, the preparation of a fresh tissue sample to make it accessible to microscopic evaluation.

gross motor skills

The group of motor skills (including walking, running, and throwing) that require large muscle groups to produce the major action, and require less precision than that exerted by small muscles. Most motor activities combine some elements of both fine and gross motor function.


1. Basic substance or foundation. 2. Reduced to a powder; pulverized. 3. In electronics, the negative or earth pole that has zero electrical potential.

ground ivy

An aromatic evergreen perennial (Glechoma hederacea) of the mint family, native to Europe and southwestern Asia and now common in most of North America. The plant is used in herbal teas, in cooking, and as a salad green; and in herbal medicine to treat disorders of the ear, nose, throat, and digestive system.

ground state

The state of the lowest energy of a system such as an atom or molecule.

ground strike

Electrocution by lightning after electrical energy hits the ground and spreads outward toward a victim.

ground transportation

In medical services, the use of ambulances to convey patients to health care facilities.

ground truth

1. Unvarnished data. 2. Actual or incontrovertible facts. 3. The mean of all data collected. A reference standard based on multiple observations.


(groop) A number of similar objects or structures considered together, e.g., bacteria with similar metabolic characteristics. Atomic molecules and compounds with similar structures or properties are classified with certain groups.

alcohol g. The hydroxyl, —OH, which imparts alcoholic characteristics to organic compounds. These exist in three forms: primary, —CH2OH; secondary, = CHOH; and tertiary, ≡COH.

amino acid g. The NH2 group that characterizes the amines.

blood g. SEE: blood group.

carbonyl g. Carbonyl.

clinical cooperative g. A network of clinicians and scientists who work together from widely separated locations to study and treat relatively rare diseases, e.g., certain forms of cancer. In cancer care, prominent clinical cooperative groups include the Children’s Oncology Group (COG), the Gynecology Oncology Group (GOG), and the Eastern Cooperative Oncology Group (ECOG).

colon-typhoid-dysentery g. The collective term for Escherichia, Salmonella, and Shigella bacteria.

control g. Control (4).

diagnosis-related g....

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