Definition of "multigraph"

(graph theory) A set V (whose elements are called vertices or nodes), taken together with a multiset E, each of whose elements (called an edge or line) is a cardinality-two multisubset of V.  examples

(graph theory, less commonly) A set V (as before), taken together with a multiset E, each of whose elements is a cardinality-two subset of V.  examples

(historical, printing) A combined rotary typesetting and printing machine for office use. The type is transferred semi-automatically by means of keys from a type-supply drum to a printing drum. The printing may be done by means of an inked ribbon to print "typewritten" letters, or directly from inked type or a stereotype plate, as in a printing press.

(linguistics) A specific sequence of letters treated as a (phonemic) unit.  examples

(historical, transitive) To print using a multigraph machine.