Webster's New World Medical Dictionary

GERD
Gastroesophageal reflux disease.
germ cell
Either the egg or the sperm cell; a
reproductive cell. Each mature germ cell is haploid,
meaning that it has a single set of 23 chromosomes
containing half the usual amount of DNA and half
the usual number of genes. Except for the egg and
the sperm, most cells in the human body contain the
entire human genome. Also known as a gamete.
germ cell tumor
A tumor that arises from a germ
cell. A germ cell tumor may arise within the gonads
(in the ovary or testis). Most testicular tumors, in
fact, are germ cell tumors. Germ cell tumors also may
arise in extragonadal sites, reflecting the fact that
germ cells travel to diverse areas of the body, such as
the chest, abdomen, and brain.
German measles
See 
rubella.
German measles immunization
See 
MMR.
germinoma
A rare cancer of the germ cells (the
tissue that normally differentiates to become the
eggs or sperm cells).
gestalt therapy
An older psychotherapeutic con-
cept that stresses understanding mental processes
as holistic entities (gestalts) rather than as discrete
steps. Gestalt therapy often uses group therapy tech-
niques to help patients gain this type of insight. See
also 
group therapy.
gestation
The period of time from conception to
birth.
gestational diabetes
See 
diabetes, gestational.
GI tract
See 
gastrointestinal tract.
giant cell arteritis
See 
arteritis, cranial.
giant cell pneumonia
See 
pneumonia, giant
cell.
giant cell tumor of bone
A tumor of bone char-
acterized by massive destruction of the end (epiph-
ysis) of a long bone. The site most commonly
involved by this tumor is the knee, both the far end
of the femur and the near end of the tibia. The term
“giant cell” reflects the fact that microscopic analy-
sis of the tumor reveals large multinucleate cells
(cells with more than one nucleus). The tumor is
often coated by new bony growth. It causes pain,
restricts movement, and is usually malignant.
Treatment is by surgery, usually followed by
chemotherapy.