gum·mer I. \ˈgəmə(r), dial ˈgüm-\noun (-s) 1.: a tool or machine for gumming a worn saw 2.: an old sheep that has lost all its teeth II. \ˈgəmə(r)\noun (-s) Etymology:gum (IV) + -er 1.: one that applies gum or glue (as to envelopes, labels, or tape) 2.: a person that gathers gum from the trees that produce it