Any of various viscous substances that are exuded by certain plants and trees and dry into water-soluble, noncrystalline, brittle solids. A similar plant exudate, such as a resin. Any of various adhesives made from such exudates or other sticky substance. A substance resembling the viscous substance exuded by certain plants, as in stickiness. Any of various trees of the genera Eucalyptus, Liquidambar, or Nyssa that are sources of gum. Also called gum tree. The wood of such a tree; gumwood. Chewing gum. To cover, smear, seal, fill, or fix in place with or as if with gum. To exude or form gum. To become sticky or clogged. gum up To ruin or bungle: gum up the works. The firm connective tissue covered by mucous membrane that envelops the alveolar arches of the jaw and surrounds the bases of the teeth. Also called gingiva. To chew (food) with toothless gums.