fuller’s earth
  Highly adsorbent (attaches to other substances without any chemical
  action) clay-like substance consisting of hydrated aluminum silicates;
  used in talcum powders.

fly blister
  Blister caused by the vesicating (blistering) body fluid of certain
  beetles.

fusiform
  Tapered at each end; spindle-shaped.

galatea
  Durable, often striped cotton fabric used in making clothing.

galax (beetleweed, coltsfoot, wandflower)
  Stemless evergreen perennial plant (Galax urceolata) of the eastern us,
  with a rosette of glossy, heart-shaped leaves and small white flowers in
  spike-like clusters.

gallic acid
  Colorless crystalline compound, C7H6O5, derived from tannin used as a
  tanning agent, ink dye, in photography, and paper manufacturing.

gamboge
  Brownish or orange resin from trees of the genus Garcinia of
  south-central Asia and yielding a golden-yellow pigment.

gaucherie
  Awkward or tactless act, manner, or expression.

gelsemium
  Genus of climbing plants.  The yellow (false) jasmine (Gelsemium
  sempervirens) is a native of the Southern United States; the root is
  used for malarial fevers.

gentian
  Plants of the genus Gentiana, having showy, variously colored flowers. 
  The dried rhizome and roots of a yellow-flowered European gentian, G.
  lutea, used as a tonic.

germander
  Aromatic plants of the genus Teucrium, with purplish or reddish flowers.

gingham
  Yarn-dyed cotton fabric woven in stripes, checks, plaids, or solid
  colors.

glace
  Smooth, glazed or glossy surface, such as certain silks or leathers. 
  Coated with a sugar glaze; candied.

glairy
  Slimy consistency, like egg white; cough producing glairy sputum.

glanders
  Contagious, usually fatal disease of horses, caused by the bacterium
  Pseudomonas mallei; causes swollen lymph nodes, nasal discharge, and
  ulcers of the respiratory tract and skin.  Communicable to other mammals,
  including humans.

glaubers salts
  (Na2so4.10H2O); colorless salt used as a cathartic.

gleet
  Inflammation of the urethra caused by chronic gonorrhea with a discharge
  of mucus and pus; the discharge that is characteristic of this
  inflammation.

Glonoin
  Dilute solution of nitroglycerin used as a neurotic.

glycerite
  Preparation made by mixing or dissolving a substance in glycerin.

glycyrrhiza
  Widely distributed perennial herbs of the family Leguminosae that
  include licorice.  Dried root of a licorice of the genus Glycyrrhiza (G.
  glabra); used to mask unpleasant flavors in drugs or to give a pleasant
  taste to confections called licorice.

goiter (goitre)
  Enlargement of the thyroid gland; often results from insufficient intake
  of iodine.