Grattage. a method of drawing by scratching paper or cardboard that has been covered with india ink with a pen or a sharp instrument. The grattage process is reminiscent of scraping an oiled surface in lithography.rattage. a method of drawing by scratching paper or cardboard that has been covered with india ink with a pen or a sharp instrument. The grattage process is reminiscent of scraping an oiled surface in lithography.
3. (Zoology) of or relating to the surface of an animal, such as a jellyfish, on which the mouth is situated. 4. (Medicine) denoting a drug to be taken by mouth Compare parenteral: an oral contraceptive.
Tooth, plural teeth, any of the hard, resistant structures occurring on the jaws and in or around the mouth and pharynx areas of vertebrates. Teeth are used for catching and masticating food, for defense, and for other specialized purposes. The teeth of vertebrates represent the modified descendants of bony dermal (skin) plates that armoured ancestral fishes. A tooth consists of a crown and one or more roots. The crown is the functional part that is visible above the gum. The root is the unseen portion that supports and fastens the tooth in the jawbone.